- inward
- inward collapse of carbuncle toxin
- inwardness
- inward normal
- inward rectification
- inward rectifying potassium channel
- inward thrust fault
- inward turning inlet
- inward variation
- In-Yer-Face Theatre
- in极小原理
- I/O
- IO
- Io
- IOA
- Ioan Grigorescu
- Ioannina
- Ioannity
- IOBC
- I. O. Bendixson
- I. O. Bendixson (1861—1935)
- IOCAS
- Iocaste
- IOCG
- IOC Olympic Prize for Sports Sciences