Usage (2)

apropos [-r|-w] keyword
whatis [-r|-w] keyword

apropos or whatis searches the short description of each manpage (at the end of the Name section) for the given keyword. 

-r lets you use a regular expression in your keyword
-w lets you do wildcard (shell-style globbing) matches.

[jon@razorback jon]$ apropos remote
rlogin (1)           - remote login
rlogind (8)          - remote login server
[ . . . more . . . ]