- irridenta
- irridentist
- irritable bowel syndrome
- irritant
- irritated
- irritably
- irrigation ditch
- irritation (esp. in the throat)
- irrupt
- irritative
- irtish
- irruptive
- irruption
- irtysh
- irtysh river
- irtish river
- irula
- irving
- irving berlin
- irving howe
- irving langmuir
- is inted
- irvingia
- is tethered
- is synonymous with (which please see)]
- isaac
- is to be at your disposal
- isaac asimov
- is voice is breaking he should no longer sing in the choir
- isaac hull
- isaac bashevis singer
- isaac m. singer
- isaac merrit singer
- isaac newton
- isaac mayer wise
- isaac stern
- isabella i
- isabella
- isabella stewart gardner
- isabella the catholic
- isaiah
- isadora duncan
- ischaemia
- isarithm
- isamu noguchi
- isak dinesen
- ischemia
- ischaemic stroke
- ischemic anoxia
- ischemic hypoxia