2. Initialism. (legal) proof of service ¹
3. Initialism. (linguistics) part of speech (''noun, verb, interjection etc.'') ¹
4. Initialism. (context: retail) point of sale / point of service ¹
5. Initialism. (technology) Proprietary Operating System ¹
6. Initialism. (context: vulgar or humorous pejorative slang of a person or thing) piece of shit ¹
7. Adjective. (UK slang) positive ¹
¹ Source: wiktionary.com
Definition of Pos
1. po [n] - See also: po