diff --git a/man5/proc.5 b/man5/proc.5
index efcfa9aed..d487e2eac 100644
--- a/man5/proc.5
+++ b/man5/proc.5
@@ -2038,7 +2038,9 @@ Memory which is actively being written back to the disk.
 Non-file backed pages mapped into user-space page tables.
 .TP
 .IR Mapped " %lu"
-Files which have been mmaped, such as libraries.
+Files which have been mapped into memory (with
+.BR mmap (2)),
+such as libraries.
 .TP
 .IR Shmem " %lu (since Linux 2.6.32)"
 [To be documented.]