diff --git a/man2/read.2 b/man2/read.2
index 4508941dc..bb46ae291 100644
--- a/man2/read.2
+++ b/man2/read.2
@@ -180,6 +180,13 @@ or to return the number of bytes already read.
 .SH CONFORMING TO
 SVr4, 4.3BSD, POSIX.1-2001.
 .SH NOTES
+The types
+.I size_t
+and
+.I ssize_t
+are, respectively,
+unsigned and signed integer data types specified by POSIX.1.
+
 On Linux,
 .BR read ()
 (and similar system calls) will transfer at most