Normally used as in what you are and aren't allowed to do with your InterNet connection by your ISP, place of education or place of work.
Standard examples for residential service include:
See HoihoAcceptableUsePolicy for the WlugServer AUP, and http://www.wlug.org.nz/archive/mailing-list-aup.txt.
4 pages link to AcceptableUsePolicy: