An Etymological Dictionary of Astronomy and Astrophysics

1a) An intervening time; interval; meantime.

1b) A temporary or provisional arrangement.

2. For, during, belonging to, or connected with an intervening period of time; temporary; provisional (Dictionary.com).

Etymology (EN): L. interim (adv.) “in the meantime, meanwhile,” originally “in the midst of that,” from → inter- “between” + im, an old accusative of “is, he, this, that.”

Etymology (PE): Andarim, from andar-, → inter-, + im variant em “this;” Mid.Pers. im “this;” from Old.Pers./Av. ima “this;” Skt. ima; cf. Lori (Laki) im “this side.” The Mid.Pers. im occurs in Mod.Pers. as em- in emruz “today,” emšab “tonight,” and emsâl “this year.”