diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 6715f65..5abc4e9 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -5304,6 +5304,14 @@
 	command is given.  If the Normal group colors are changed later, the
 	"fg" and "bg" colors will not be adjusted.
 
+ctermfont={font-nr}				*highlight-ctermfont*
+	This gives the alternative font number to use in the terminal. The
+	available fonts depend on the terminal, and if the terminal is not set
+	up for alternative fonts this simply won't do anything. The range of
+	{font-nr} is 0-10 where 0 resets the font to the default font, 1-9
+	selects one of the 9 alternate fonts, and 10 selects the Fraktur font.
+	For more information see your terminal's handling of SGR parameters
+	10-20. |t_CF|
 
 3. highlight arguments for the GUI