diff --git a/boot_control_chromeos.cc b/boot_control_chromeos.cc
index 724dab0..40fc349 100644
--- a/boot_control_chromeos.cc
+++ b/boot_control_chromeos.cc
@@ -149,20 +149,21 @@
 bool BootControlChromeOS::GetPartitionDevice(const string& partition_name,
                                              unsigned int slot,
                                              string* device) const {
-  // Partition name prefixed with |kPartitionNamePrefixDlc| is a DLC.
+  // Partition name prefixed with |kPartitionNamePrefixDlc| is a DLC module.
   if (base::StartsWith(partition_name,
                        kPartitionNamePrefixDlc,
                        base::CompareCase::SENSITIVE)) {
-    // Extract DLC ID from partition_name (DLC ID is the string after
-    // |kPartitionNamePrefixDlc| in partition_name).
-    const auto dlc_id = partition_name.substr(strlen(kPartitionNamePrefixDlc));
-    if (dlc_id.empty()) {
-      LOG(ERROR) << " partition name does not contain dlc id:"
+    // Extract DLC module ID from partition_name (DLC module ID is the string
+    // after |kPartitionNamePrefixDlc| in partition_name).
+    const auto dlc_module_id =
+        partition_name.substr(strlen(kPartitionNamePrefixDlc));
+    if (dlc_module_id.empty()) {
+      LOG(ERROR) << " partition name does not contain DLC module ID:"
                  << partition_name;
       return false;
     }
     *device = base::FilePath(kDlcInstallRootDirectoryEncrypted)
-                  .Append(dlc_id)
+                  .Append(dlc_module_id)
                   .Append(slot == 0 ? kPartitionNameDlcA : kPartitionNameDlcB)
                   .Append(kPartitionNameDlcImage)
                   .value();
diff --git a/client_library/client_dbus.cc b/client_library/client_dbus.cc
index 2257d2e..e0d1f64 100644
--- a/client_library/client_dbus.cc
+++ b/client_library/client_dbus.cc
@@ -57,14 +57,14 @@
       nullptr);
 }
 
-bool DBusUpdateEngineClient::AttemptInstall(const string& omaha_url,
-                                            const vector<string>& dlc_ids) {
+bool DBusUpdateEngineClient::AttemptInstall(
+    const string& omaha_url, const vector<string>& dlc_module_ids) {
   // Convert parameters into protobuf.
   chromeos_update_engine::DlcParameters dlc_parameters;
   dlc_parameters.set_omaha_url(omaha_url);
-  for (const auto& dlc_id : dlc_ids) {
+  for (const auto& dlc_module_id : dlc_module_ids) {
     chromeos_update_engine::DlcInfo* dlc_info = dlc_parameters.add_dlc_infos();
-    dlc_info->set_dlc_id(dlc_id);
+    dlc_info->set_dlc_id(dlc_module_id);
   }
   string dlc_request;
   if (dlc_parameters.SerializeToString(&dlc_request)) {
diff --git a/client_library/client_dbus.h b/client_library/client_dbus.h
index 0fa2cc3..a186d45 100644
--- a/client_library/client_dbus.h
+++ b/client_library/client_dbus.h
@@ -42,7 +42,7 @@
                      bool at_user_request) override;
 
   bool AttemptInstall(const std::string& omaha_url,
-                      const std::vector<std::string>& dlc_ids) override;
+                      const std::vector<std::string>& dlc_module_ids) override;
 
   bool GetStatus(int64_t* out_last_checked_time,
                  double* out_progress,
diff --git a/client_library/include/update_engine/client.h b/client_library/include/update_engine/client.h
index 183768d..1bc6111 100644
--- a/client_library/include/update_engine/client.h
+++ b/client_library/include/update_engine/client.h
@@ -48,16 +48,17 @@
                              const std::string& omaha_url,
                              bool at_user_request) = 0;
 
-  // Request the update_engine to install a list of DLC.
+  // Request the update_engine to install a list of DLC modules.
   // |omaha_url|
   //     Force update_engine to look for updates from the given server. Passing
   //     empty indicates update_engine should use its default value. Note that
   //     update_engine will ignore this parameter in production mode to avoid
   //     pulling untrusted updates.
-  // |dlc_ids|
-  //     A vector of DLC IDs.
-  virtual bool AttemptInstall(const std::string& omaha_url,
-                              const std::vector<std::string>& dlc_ids) = 0;
+  // |dlc_module_ids|
+  //     A list of DLC module IDs.
+  virtual bool AttemptInstall(
+      const std::string& omaha_url,
+      const std::vector<std::string>& dlc_module_ids) = 0;
 
   // Returns the current status of the Update Engine.
   //
diff --git a/common_service.cc b/common_service.cc
index 213267c..6420b65 100644
--- a/common_service.cc
+++ b/common_service.cc
@@ -106,8 +106,9 @@
 
 bool UpdateEngineService::AttemptInstall(brillo::ErrorPtr* error,
                                          const string& omaha_url,
-                                         const vector<string>& dlc_ids) {
-  if (!system_state_->update_attempter()->CheckForInstall(dlc_ids, omaha_url)) {
+                                         const vector<string>& dlc_module_ids) {
+  if (!system_state_->update_attempter()->CheckForInstall(dlc_module_ids,
+                                                          omaha_url)) {
     // TODO(xiaochu): support more detailed error messages.
     LogAndSetError(error, FROM_HERE, "Could not schedule install operation.");
     return false;
diff --git a/common_service.h b/common_service.h
index dbf897e..f93855d 100644
--- a/common_service.h
+++ b/common_service.h
@@ -53,12 +53,12 @@
                      int32_t in_flags_as_int,
                      bool* out_result);
 
-  // Attempts a DLC install operation.
+  // Attempts a DLC module install operation.
   // |omaha_url|: the URL to query for update.
-  // |dlc_ids|: a list of DLC IDs.
+  // |dlc_module_ids|: a list of DLC module IDs.
   bool AttemptInstall(brillo::ErrorPtr* error,
                       const std::string& omaha_url,
-                      const std::vector<std::string>& dlc_ids);
+                      const std::vector<std::string>& dlc_module_ids);
 
   bool AttemptRollback(brillo::ErrorPtr* error, bool in_powerwash);
 
diff --git a/dbus_service.cc b/dbus_service.cc
index 0eec01d..03425b6 100644
--- a/dbus_service.cc
+++ b/dbus_service.cc
@@ -73,16 +73,17 @@
     return false;
   }
   // Extract fields from the protobuf.
-  vector<string> dlc_ids;
+  vector<string> dlc_module_ids;
   for (const auto& dlc_info : dlc_parameters.dlc_infos()) {
     if (dlc_info.dlc_id().empty()) {
       *error = brillo::Error::Create(
           FROM_HERE, "update_engine", "INTERNAL", "parameters are invalid.");
       return false;
     }
-    dlc_ids.push_back(dlc_info.dlc_id());
+    dlc_module_ids.push_back(dlc_info.dlc_id());
   }
-  return common_->AttemptInstall(error, dlc_parameters.omaha_url(), dlc_ids);
+  return common_->AttemptInstall(
+      error, dlc_parameters.omaha_url(), dlc_module_ids);
 }
 
 bool DBusUpdateEngineService::AttemptRollback(ErrorPtr* error,
diff --git a/mock_update_attempter.h b/mock_update_attempter.h
index eaa0785..c5fcec8 100644
--- a/mock_update_attempter.h
+++ b/mock_update_attempter.h
@@ -53,7 +53,7 @@
                     UpdateAttemptFlags flags));
 
   MOCK_METHOD2(CheckForInstall,
-               bool(const std::vector<std::string>& dlc_ids,
+               bool(const std::vector<std::string>& dlc_module_ids,
                     const std::string& omaha_url));
 
   MOCK_METHOD0(RefreshDevicePolicy, void(void));
diff --git a/omaha_request_action.cc b/omaha_request_action.cc
index 6adacc3..9cb9b49 100644
--- a/omaha_request_action.cc
+++ b/omaha_request_action.cc
@@ -437,14 +437,15 @@
                          install_date_in_days,
                          system_state);
   }
-  // Create APP ID according to |dlc_id| (sticking the current AppID to the DLC
-  // ID with an underscode).
-  for (const auto& dlc_id : params->dlc_ids()) {
-    OmahaAppData dlc_app = {.id = params->GetAppId() + "_" + dlc_id,
-                            .version = params->app_version()};
+  // Create APP ID according to |dlc_module_id| (sticking the current AppID to
+  // the DLC module ID with an underscode).
+  for (const auto& dlc_module_id : params->dlc_module_ids()) {
+    OmahaAppData dlc_module_app = {
+        .id = params->GetAppId() + "_" + dlc_module_id,
+        .version = params->app_version()};
     app_xml += GetAppXml(event,
                          params,
-                         dlc_app,
+                         dlc_module_app,
                          ping_only,
                          include_ping,
                          false, /* skip_updatecheck */
diff --git a/omaha_request_action_unittest.cc b/omaha_request_action_unittest.cc
index 06d937d..c758fbd 100644
--- a/omaha_request_action_unittest.cc
+++ b/omaha_request_action_unittest.cc
@@ -317,7 +317,7 @@
     request_params_.set_rollback_allowed(false);
     request_params_.set_is_powerwash_allowed(false);
     request_params_.set_is_install(false);
-    request_params_.set_dlc_ids({});
+    request_params_.set_dlc_module_ids({});
 
     fake_system_state_.set_request_params(&request_params_);
     fake_system_state_.set_prefs(&fake_prefs_);
@@ -3103,7 +3103,7 @@
 TEST_F(OmahaRequestActionTest, InstallTest) {
   OmahaResponse response;
   request_params_.set_is_install(true);
-  request_params_.set_dlc_ids({"dlc_no_0", "dlc_no_1"});
+  request_params_.set_dlc_module_ids({"dlc_no_0", "dlc_no_1"});
   brillo::Blob post_data;
   ASSERT_TRUE(TestUpdateCheck(fake_update_response_.GetUpdateResponse(),
                               -1,
@@ -3119,10 +3119,10 @@
                               &post_data));
   // Convert post_data to string.
   string post_str(post_data.begin(), post_data.end());
-  for (const auto& dlc_id : request_params_.dlc_ids()) {
+  for (const auto& dlc_module_id : request_params_.dlc_module_ids()) {
     EXPECT_NE(string::npos,
               post_str.find("appid=\"" + fake_update_response_.app_id + "_" +
-                            dlc_id + "\""));
+                            dlc_module_id + "\""));
   }
   EXPECT_NE(string::npos,
             post_str.find("appid=\"" + fake_update_response_.app_id + "\""));
@@ -3134,14 +3134,14 @@
     updatecheck_count++;
     pos++;
   }
-  EXPECT_EQ(request_params_.dlc_ids().size(), updatecheck_count);
+  EXPECT_EQ(request_params_.dlc_module_ids().size(), updatecheck_count);
 }
 
 TEST_F(OmahaRequestActionTest, InstallMissingPlatformVersionTest) {
   fake_update_response_.multi_app_skip_updatecheck = true;
   fake_update_response_.multi_app_no_update = false;
   request_params_.set_is_install(true);
-  request_params_.set_dlc_ids({"dlc_no_0", "dlc_no_1"});
+  request_params_.set_dlc_module_ids({"dlc_no_0", "dlc_no_1"});
   request_params_.set_app_id(fake_update_response_.app_id_skip_updatecheck);
   OmahaResponse response;
   ASSERT_TRUE(TestUpdateCheck(fake_update_response_.GetUpdateResponse(),
diff --git a/omaha_request_params.cc b/omaha_request_params.cc
index 4b72328..c458424 100644
--- a/omaha_request_params.cc
+++ b/omaha_request_params.cc
@@ -123,7 +123,7 @@
   // Set the interactive flag accordingly.
   interactive_ = in_interactive;
 
-  dlc_ids_.clear();
+  dlc_module_ids_.clear();
   // Set false so it will do update by default.
   is_install_ = false;
   return true;
diff --git a/omaha_request_params.h b/omaha_request_params.h
index 1bebf1c..1bfa471 100644
--- a/omaha_request_params.h
+++ b/omaha_request_params.h
@@ -165,10 +165,13 @@
   inline int64_t max_update_checks_allowed() const {
     return max_update_checks_allowed_;
   }
-  inline void set_dlc_ids(const std::vector<std::string>& dlc_ids) {
-    dlc_ids_ = dlc_ids;
+  inline void set_dlc_module_ids(
+      const std::vector<std::string>& dlc_module_ids) {
+    dlc_module_ids_ = dlc_module_ids;
   }
-  inline std::vector<std::string> dlc_ids() const { return dlc_ids_; }
+  inline std::vector<std::string> dlc_module_ids() const {
+    return dlc_module_ids_;
+  }
   inline void set_is_install(bool is_install) { is_install_ = is_install; }
   inline bool is_install() const { return is_install_; }
 
@@ -336,12 +339,12 @@
   // When reading files, prepend root_ to the paths. Useful for testing.
   std::string root_;
 
-  // A list of DLC ID to install.
-  std::vector<std::string> dlc_ids_;
+  // A list of DLC module IDs to install.
+  std::vector<std::string> dlc_module_ids_;
 
   // This variable defines whether the payload is being installed in the current
-  // partition. At the moment, his is used for installing DLCs on the current
-  // active partition instead of the inactive partition.
+  // partition. At the moment, this is used for installing DLC modules on the
+  // current active partition instead of the inactive partition.
   bool is_install_;
 
   DISALLOW_COPY_AND_ASSIGN(OmahaRequestParams);
diff --git a/update_attempter.cc b/update_attempter.cc
index 6019e6d..f47a63e 100644
--- a/update_attempter.cc
+++ b/update_attempter.cc
@@ -419,8 +419,8 @@
     // target channel.
     omaha_request_params_->UpdateDownloadChannel();
   }
-  // Set the DLC ID list.
-  omaha_request_params_->set_dlc_ids(dlc_ids_);
+  // Set the DLC module ID list.
+  omaha_request_params_->set_dlc_module_ids(dlc_module_ids_);
   omaha_request_params_->set_is_install(is_install_);
 
   LOG(INFO) << "target_version_prefix = "
@@ -797,7 +797,7 @@
 bool UpdateAttempter::CheckForUpdate(const string& app_version,
                                      const string& omaha_url,
                                      UpdateAttemptFlags flags) {
-  dlc_ids_.clear();
+  dlc_module_ids_.clear();
   is_install_ = false;
   bool interactive = !(flags & UpdateAttemptFlags::kFlagNonInteractive);
 
@@ -840,8 +840,8 @@
   }
 
   if (forced_update_pending_callback_.get()) {
-    if (!system_state_->dlcservice()->GetInstalled(&dlc_ids_)) {
-      dlc_ids_.clear();
+    if (!system_state_->dlcservice()->GetInstalled(&dlc_module_ids_)) {
+      dlc_module_ids_.clear();
     }
     // Make sure that a scheduling request is made prior to calling the forced
     // update pending callback.
@@ -852,9 +852,9 @@
   return true;
 }
 
-bool UpdateAttempter::CheckForInstall(const vector<string>& dlc_ids,
+bool UpdateAttempter::CheckForInstall(const vector<string>& dlc_module_ids,
                                       const string& omaha_url) {
-  dlc_ids_ = dlc_ids;
+  dlc_module_ids_ = dlc_module_ids;
   is_install_ = true;
   forced_omaha_url_.clear();
 
diff --git a/update_attempter.h b/update_attempter.h
index 2d020fa..07a66b9 100644
--- a/update_attempter.h
+++ b/update_attempter.h
@@ -149,7 +149,7 @@
                               UpdateAttemptFlags flags);
 
   // This is the version of CheckForUpdate called by AttemptInstall API.
-  virtual bool CheckForInstall(const std::vector<std::string>& dlc_ids,
+  virtual bool CheckForInstall(const std::vector<std::string>& dlc_module_ids,
                                const std::string& omaha_url);
 
   // This is the internal entry point for going through a rollback. This will
@@ -524,8 +524,8 @@
   std::string forced_app_version_;
   std::string forced_omaha_url_;
 
-  // A list of DLC IDs.
-  std::vector<std::string> dlc_ids_;
+  // A list of DLC module IDs.
+  std::vector<std::string> dlc_module_ids_;
   // Whether the operation is install (write to the current slot not the
   // inactive slot).
   bool is_install_;
diff --git a/update_attempter_unittest.cc b/update_attempter_unittest.cc
index 676f13a..a395e1b 100644
--- a/update_attempter_unittest.cc
+++ b/update_attempter_unittest.cc
@@ -1185,8 +1185,8 @@
                            testing::Return(true)));
 
   attempter_.CheckForUpdate("", "autest", UpdateAttemptFlags::kNone);
-  EXPECT_EQ(attempter_.dlc_ids_.size(), 1);
-  EXPECT_EQ(attempter_.dlc_ids_[0], dlc_module_id);
+  EXPECT_EQ(attempter_.dlc_module_ids_.size(), 1);
+  EXPECT_EQ(attempter_.dlc_module_ids_[0], dlc_module_id);
 }
 
 TEST_F(UpdateAttempterTest, CheckForUpdateAUTest) {
diff --git a/update_engine_client.cc b/update_engine_client.cc
index 9d1e093..f36949b 100644
--- a/update_engine_client.cc
+++ b/update_engine_client.cc
@@ -296,7 +296,7 @@
   DEFINE_bool(last_attempt_error, false, "Show the last attempt error.");
   DEFINE_bool(eol_status, false, "Show the current end-of-life status.");
   DEFINE_bool(install, false, "Requests an install.");
-  DEFINE_string(dlc_ids, "", "colon-separated list of DLC IDs.");
+  DEFINE_string(dlc_module_ids, "", "colon-separated list of DLC IDs.");
 
   // Boilerplate init commands.
   base::CommandLine::Init(argc_, argv_);
@@ -481,24 +481,26 @@
   }
 
   if (FLAGS_install) {
-    // Parse DLC IDs.
-    vector<string> dlc_ids;
-    if (!FLAGS_dlc_ids.empty()) {
-      dlc_ids = base::SplitString(
-          FLAGS_dlc_ids, ":", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
+    // Parse DLC module IDs.
+    vector<string> dlc_module_ids;
+    if (!FLAGS_dlc_module_ids.empty()) {
+      dlc_module_ids = base::SplitString(FLAGS_dlc_module_ids,
+                                         ":",
+                                         base::TRIM_WHITESPACE,
+                                         base::SPLIT_WANT_ALL);
     }
-    if (dlc_ids.empty()) {
-      LOG(ERROR) << "dlc_ids is empty:" << FLAGS_dlc_ids;
+    if (dlc_module_ids.empty()) {
+      LOG(ERROR) << "dlc_module_ids is empty:" << FLAGS_dlc_module_ids;
       return 1;
     }
-    if (!client_->AttemptInstall(FLAGS_omaha_url, dlc_ids)) {
+    if (!client_->AttemptInstall(FLAGS_omaha_url, dlc_module_ids)) {
       LOG(ERROR) << "AttemptInstall failed.";
       return 1;
     }
     return 0;
-  } else if (!FLAGS_dlc_ids.empty()) {
-    LOG(ERROR) << "dlc_ids is not empty while install is not set:"
-               << FLAGS_dlc_ids;
+  } else if (!FLAGS_dlc_module_ids.empty()) {
+    LOG(ERROR) << "dlc_module_ids is not empty while install is not set:"
+               << FLAGS_dlc_module_ids;
     return 1;
   }