diff --git a/usr.bin/top/top.local.1 b/usr.bin/top/top.local.1
index f3b01460b69c..a674828b829b 100644
--- a/usr.bin/top/top.local.1
+++ b/usr.bin/top/top.local.1
@@ -24,7 +24,7 @@ number of bytes active
 number of bytes inactive
 .TP
 .B Wired:
-number of bytes wired down, including cached file data pages
+number of bytes wired down, including BIO-level cached file data pages
 .TP
 .B Cache:
 number of clean bytes caching data that are available for