- (law, uncountable) intellectual property
- (motion picture, countable) interpositive
- (baseball, countable, invariant) The statistic reporting the number of innings pitched by a pitcher.
- (biology, uncountable) immunoprecipitation
- (computing) insertion point (where text, etc. will be added in a document)
- (US, military, initialism, slang) An Iraqi police officer, or the Iraqi police as a whole.
- (US, military, initialism, slang) An Irish pennant.
- (grammar, X-bar theory) Inflectional phrase
- (inflectional phrase): XP
- (Internet, networking) Internet Protocol
- Ingress Protection Rating
- International Paper
- (cryptography) initial permutation
- (Internet Protocol): TCP/IP