from
mdoc(7):
Code:
Under FreeBSD 6.2, the following sections are defined:
1 FreeBSD General Commands Manual
2 FreeBSD System Calls Manual
3 FreeBSD Library Functions Manual
4 FreeBSD Kernel Interfaces Manual
5 FreeBSD File Formats Manual
6 FreeBSD Games Manual
7 FreeBSD Miscellaneous Information Manual
8 FreeBSD System Manager's Manual
9 FreeBSD Kernel Developer's Manual
Sometimes a manpage occurs in two (or more?) sections, for example
chmod(1) deals with the chmod command, while
chmod(2) deals with the chmod() system call.