An Acronym for Display Power Management System.
Allows a monitor to change its power usage state to Standby, Suspend, and Off.
If you have a new enough monitor, you can use the xset(1) command to change the default timeouts.
in your /etc/X11/XF86Config file, in the Monitor section''
"xset q" shows the current status. (It says disabled). "xset +dpms" enables dpms. The last command says "go into Standby mode after 300 seconds without user input, Suspend mode after 600 seconds, and Off after 900 seconds".