From Longman Dictionary of Contemporary Englishin-betweenˌin-ˈbetween adjective MIDDLEin the middle between two points, sizes, periods of time etc → midpoint She was at that in-between age, neither a girl nor a woman.
Examples from the Corpus
in-between• She's at that in-between age, neither a girl nor a woman.• It was a strange in-between time for Manila, a time when the bind seemed especially strangling. 