The following is quoted from Wikipedia's disambiguation page of Ass, except the last bullet.

Ass may refer to:

• donkey or any member of the subgenus Asinus
• arse, a word for the anus or the buttocks
• buffoon, a term for a clumsy or stupid person
• as (coin), a Roman weight and unit of money
• Áss in Norse mythology
• Asso, the Italian city
• Ass (album), a 1973 album by the band Badfinger
• Asshole (game), a card game also known as Ass

The acronym ASS stands for:

• ASS (gene), a human gene that encodes for the enzyme argininosuccinate synthetase
• ASS (car), made in France from 1919 to 1920
• American Science and Surplus, a seller of surplus and educational goods
• ASS, the rail code for Alness, United Kingdom
• Advanced SubStation Alpha, a subtitles format
• Angle-Side-Side, a faulty proof of congruency of two triangles (also called SSA)
• American Sociological Association, known as the American Sociological Society until 1959
• Austrian Social Service, an Austrian non-profit organization
• Authorized Service Shop, of Tai Ling Motor Co. Ltd., a manufacturer partner of Suzuki Motor Corp.