2. Initialism. (Internet) original post ¹
3. Initialism. (military) observation post ¹
4. Initialism. (publishing) out of print ¹
5. Initialism. (qualifier religious) Order of Preachers, the Dominicans, a religious order ¹
6. Initialism. overproof ¹
7. Initialism. Overall Position ¹
8. Initialism. (gaming) overpowered (adj.) ¹
9. Initialism. (soplink online pharmacy) ¹
10. Initialism. (alternative capitalization of OP) (''original post'', ''original poster'') ¹
11. Verb. (transitive Internet) To promote (an IRC user) to an operator. ¹
12. Noun. Op art; a style of abstract art. ¹
13. Noun. (informal sometimes pluralized) Operation. ¹
¹ Source: wiktionary.com
Definition of Op
1. a style of abstract art [n -S]