in-between

Short definition from Wiktionary

Adjective

1. 1
   Lying between; neither one thing nor the other; intermediary.

Noun

1. 1
   An interval or intervening time.
2. 2
   One who intervenes.
3. 3
   Synonym of inbetweener (“a person who or thing that falls between different groups or characteristics”).

Adverb

1. 1
   Between them.

Preposition

1. 1
   Between.
2. 2
   In the space between.