| Iolao | Iolaus |
| Iolco | Iolcos |
| Iolo Morganwg | Iolo Morganwg |
| Ion Antonescu | Ion Antonescu |
| Ion Gheorghe Maurer | Ion Gheorghe Maurer |
| Ion Iliescu | Ion Iliescu |
| Iona | Iona |
| ione | ion |
| Ione H negativo | H minus ion |
| Ioni | Ion |
| Ionia | Ionia |
| ionico | ionic |
| Ionikos | Ionikos FC |
| ionizzare | ionize |
| Iono | Ionian |
| ionosfera | ionosphere |
| Iordanes | Jordanes |
| Ioria | Leo Aiolia |
| Iorio | George |
| IOS | IOS |
| iota | jot |
| Iota Draconis | Iota Draconis |
| Iotapiano | Jotapianus |
| Iowa | Iowa |
| IP | IP |
| IP spoofing | IP address spoofing |
| Ipanema | Ipanema |
| Iparralde | Northern Basque Country |
| Ipatovo | Ipatovo |
| Ipazia | Hypatia of Alexandria |
| Ipazio | Hypatius |
| IpCop | IPCop |
| Ipecac Recordings | Ipecac Recordings |
| Ipepi | Apepi I |
| iperattivo | hyperactive |
| iperbole | hyperbola |
| iperbolico | hyperbolic |
| Ipercarica | Hypercharge |
| Ipercarica debole | Weak hypercharge |
| ipercompensare | overcompensate |
| iperconservativo | ultraconservative |
| ipercritico | captious |
| Ipergalassie | Hypergalaxy |
| iperglicemia | hyperglycemia |
| iperico | St John's wort |
| Iperide | Hypereides |
| Iperione | Hyperion |
| iperlordosi | swayback |
| ipermetropia | farsightedness |
| Ipernova | Hypernova |
| iperonimo | holonym |
| Iperplasia surrenale congenita | Congenital adrenal hyperplasia |
| Iperpotenza | Hyperpower |
| Iperrealismo | Photorealism |
| ipersensibile | hypersensitive |
| Ipersfera | N-sphere |
| Ipersuperficie | Hypersurface |
| ipertensione | hypertension |
| Ipertensione arteriosa | Hypertension |
| Ipertensione arteriosa polmonare | Pulmonary hypertension |
| Ipertensione arteriosa sistemica | Hypertension |
| ipertesto | hypertext |
| Ipertestuale | Hypertext |
| Ipertrofia prostatica benigna | Benign prostatic hyperplasia |
| iperventilazione | hyperventilation |
| iperverboso | verbose |
| Iphiclides podalirius | Scarce Swallowtail |
| Iphofen | Iphofen |
| Ipno | Hypnos |
| ipnosi | hypnosis |
| ipnotismo | hypnotism |
| ipnotizzare | mesmerize |
| ipnotizzatore | hypnotist |
