| in seta | silk |
| in sfacelo | dilapidated |
| In silico | In silico |
| in sincronia | in sync |
| in situ | in situ |
| in smoking | black-tie |
| in sordina | background |
| in sospeso | outstanding |
| In specie | Most of al |
| in staccato | staccato |
| in stato di putrefazione | decaying |
| in su | uphill |
| in successione | sequentially |
| in sé e per sé | as such |
| in tartaruga | horn-rimmed |
| in tempo | on time |
| in tensione | tense |
| in tenuta adamitica | stark naked |
| in teoria | basically |
| in termini di percentuale | in terms of percentage |
| in terra | earthen |
| In the Bedroom | In the Bedroom |
| In the Court of the Crimson King | In the Court of the Crimson King |
| In the Flat Field | In the Flat Field |
| In the Mood for Love | In the Mood for Love |
| In the Nightside Eclipse | In the Nightside Eclipse |
| In the Zone | In the Zone |
| in topless | topless |
| In toto | Unmitigate |
| in trattativa privata | by private treaty |
| In tre contro il delitto | The Regatta Mystery |
| in triplice copia | in triplicate |
| in tutte le direzioni | in every direction |
| in tutto e per tutto | outright |
