- in margine
- in medias res
- in memoriam
- in merito
- in natura
- in nuce
- in optima forma
- in optima forum
- in originali
- in pace
- in partibus infidelium
- in pectore
- in perpetuam memoriam
- in perpetuum
- in persona
- in persona Christi capitis
- in personam
- in petto
- in pleno
- in praesentia
- in publico
- in puncto
- in regula
- in rem
- in rerum natura
- in residuo
- in saecula saeculorum
- in saldo
- in silico
- in situ
- in spe
- in specie
- in statu nascendi
- in statu quo ante
- in summa
- in summo gradu
- in suo esse
- in suspenso
- in termino
- in the secondary school
- in toto
- in transitu
- in ultimis
- in unum vertere
- in utero
- in vicem
- in vino verttas
- in vitro
- in vitro fertilizace (IVF)
- in vivo