diff --git a/libc/include/bits/fcntl.h b/libc/include/bits/fcntl.h
index 597aa6e..ee5a6e1 100644
--- a/libc/include/bits/fcntl.h
+++ b/libc/include/bits/fcntl.h
@@ -43,6 +43,6 @@
  *
  * The return value depends on the operation.
  */
-int fcntl(int __fd, int __cmd, ...);
+int fcntl(int __fd, int __op, ...);
 
 __END_DECLS
diff --git a/libc/include/bits/ioctl.h b/libc/include/bits/ioctl.h
index fd31a58..260eb7d 100644
--- a/libc/include/bits/ioctl.h
+++ b/libc/include/bits/ioctl.h
@@ -40,7 +40,7 @@
 /**
  * [ioctl(2)](http://man7.org/linux/man-pages/man2/ioctl.2.html) operates on device files.
  */
-int ioctl(int __fd, int __request, ...);
+int ioctl(int __fd, int __op, ...);
 
 /*
  * Work around unsigned -> signed conversion warnings: many common ioctl
@@ -57,7 +57,7 @@
  */
 #if !defined(BIONIC_IOCTL_NO_SIGNEDNESS_OVERLOAD)
 /* enable_if(1) just exists to break overloading ties. */
-int ioctl(int __fd, unsigned __request, ...) __overloadable __enable_if(1, "") __RENAME(ioctl);
+int ioctl(int __fd, unsigned __op, ...) __overloadable __enable_if(1, "") __RENAME(ioctl);
 #endif
 
 __END_DECLS
diff --git a/libc/include/bits/lockf.h b/libc/include/bits/lockf.h
index ec6e53c..d9f5987 100644
--- a/libc/include/bits/lockf.h
+++ b/libc/include/bits/lockf.h
@@ -56,12 +56,12 @@
  *
  * See also flock().
  */
-int lockf(int __fd, int __cmd, off_t __length) __RENAME_IF_FILE_OFFSET64(lockf64) __INTRODUCED_IN(24);
+int lockf(int __fd, int __op, off_t __length) __RENAME_IF_FILE_OFFSET64(lockf64) __INTRODUCED_IN(24);
 
 /**
  * Like lockf() but allows using a 64-bit length
  * even from a 32-bit process without `_FILE_OFFSET_BITS=64`.
  */
-int lockf64(int __fd, int __cmd, off64_t __length) __INTRODUCED_IN(24);
+int lockf64(int __fd, int __op, off64_t __length) __INTRODUCED_IN(24);
 
 __END_DECLS
diff --git a/libc/include/sys/msg.h b/libc/include/sys/msg.h
index ad481a0..26071b1 100644
--- a/libc/include/sys/msg.h
+++ b/libc/include/sys/msg.h
@@ -46,7 +46,7 @@
 typedef __kernel_ulong_t msglen_t;
 
 /** Not useful on Android; disallowed by SELinux. */
-int msgctl(int __msg_id, int __cmd, struct msqid_ds* _Nullable __buf) __INTRODUCED_IN(26);
+int msgctl(int __msg_id, int __op, struct msqid_ds* _Nullable __buf) __INTRODUCED_IN(26);
 /** Not useful on Android; disallowed by SELinux. */
 int msgget(key_t __key, int __flags) __INTRODUCED_IN(26);
 /** Not useful on Android; disallowed by SELinux. */
diff --git a/libc/include/sys/prctl.h b/libc/include/sys/prctl.h
index ff03c33..1c80415 100644
--- a/libc/include/sys/prctl.h
+++ b/libc/include/sys/prctl.h
@@ -45,6 +45,6 @@
  *
  * Returns -1 and sets `errno` on failure; success values vary by option.
  */
-int prctl(int __option, ...);
+int prctl(int __op, ...);
 
 __END_DECLS
diff --git a/libc/include/sys/ptrace.h b/libc/include/sys/ptrace.h
index 022fc3a..66b30a1 100644
--- a/libc/include/sys/ptrace.h
+++ b/libc/include/sys/ptrace.h
@@ -59,7 +59,7 @@
 #define PT_GETSIGINFO PTRACE_GETSIGINFO
 #define PT_SETSIGINFO PTRACE_SETSIGINFO
 
-long ptrace(int __request, ...);
+long ptrace(int __op, ...);
 
 __END_DECLS
 
diff --git a/libc/include/sys/quota.h b/libc/include/sys/quota.h
index 79c653d..37f8925 100644
--- a/libc/include/sys/quota.h
+++ b/libc/include/sys/quota.h
@@ -51,6 +51,6 @@
  *
  * Available since API level 26.
  */
-int quotactl(int __cmd, const char* _Nullable __special, int __id, char* __BIONIC_COMPLICATED_NULLNESS __addr) __INTRODUCED_IN(26);
+int quotactl(int __op, const char* _Nullable __special, int __id, char* __BIONIC_COMPLICATED_NULLNESS __addr) __INTRODUCED_IN(26);
 
 __END_DECLS
diff --git a/libc/include/sys/reboot.h b/libc/include/sys/reboot.h
index 156d947..5d9e1a7 100644
--- a/libc/include/sys/reboot.h
+++ b/libc/include/sys/reboot.h
@@ -55,6 +55,6 @@
  * Does not return on successful reboot, returns 0 if CAD was successfully enabled/disabled,
  * and returns -1 and sets `errno` on failure.
  */
-int reboot(int __cmd);
+int reboot(int __op);
 
 __END_DECLS
diff --git a/libc/include/sys/sem.h b/libc/include/sys/sem.h
index f4256e2..5682282 100644
--- a/libc/include/sys/sem.h
+++ b/libc/include/sys/sem.h
@@ -51,7 +51,7 @@
   void* _Nullable __pad;
 };
 
-int semctl(int __sem_id, int __sem_num, int __cmd, ...) __INTRODUCED_IN(26);
+int semctl(int __sem_id, int __sem_num, int __op, ...) __INTRODUCED_IN(26);
 int semget(key_t __key, int __sem_count, int __flags) __INTRODUCED_IN(26);
 int semop(int __sem_id, struct sembuf* _Nonnull __ops, size_t __op_count) __INTRODUCED_IN(26);
 
diff --git a/libc/include/sys/shm.h b/libc/include/sys/shm.h
index 9d58046..fb6f20c 100644
--- a/libc/include/sys/shm.h
+++ b/libc/include/sys/shm.h
@@ -49,7 +49,7 @@
 /** Not useful on Android; disallowed by SELinux. */
 void* _Nonnull shmat(int __shm_id, const void* _Nullable __addr, int __flags) __INTRODUCED_IN(26);
 /** Not useful on Android; disallowed by SELinux. */
-int shmctl(int __shm_id, int __cmd, struct shmid_ds* _Nullable __buf) __INTRODUCED_IN(26);
+int shmctl(int __shm_id, int __op, struct shmid_ds* _Nullable __buf) __INTRODUCED_IN(26);
 /** Not useful on Android; disallowed by SELinux. */
 int shmdt(const void* _Nonnull __addr) __INTRODUCED_IN(26);
 /** Not useful on Android; disallowed by SELinux. */