An Acronym for Occupational Overuse Syndrome - often used to refer to sore wrists caused by constant typing (or any manual task for that matter).
OOS can be due to any overuse, like lifting etc. Carpal Tunnel Syndrome is a symptom of OOS in the wrist.
RSI is a form of OOS.
Workrave is a nice *nix/Win tool to help with OOS
2 pages link to OOS:
http://www.workrave.org/welcome/