1. 
[syn: in-between, mediate, middle]
The Collaborative International Dictionary of English v.0.48:
in-between \in-between\ adj.
   being neither at the beginning nor at the end in a series or
   time sequence; as, adolescence is an awkward in-between age.
   Syn: mediate, middle.
        [WordNet 1.5]
WordNet (r) 3.0 (2006):
in-between
    adj 1: being neither at the beginning nor at the end in a
           series; "adolescence is an awkward in-between age"; "in a
           mediate position"; "the middle point on a line" [syn:
           in-between, mediate, middle]