Setuid

From Linux 101, The beginner's guide to all things Linux.

Setuid refers to setting the "sticky bit" on an executeable for the user portion so that it may be run by other users with that users privileges. This is accomplished like so:

# chmod u+s /usr/bin/apm

That would enable any normal user to suspend the computer, normally an operation only allowed by the root user.

Note: Using setuid should be used with caution, as it can potentially be a security risk!