The story
Univerbation of in + between, perhaps in imitation of similar phrases as in the middle of, in the midst of, etc.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: Between them. Full definition →
Univerbation of in + between, perhaps in imitation of similar phrases as in the middle of, in the midst of, etc.
Etymology from Wiktionary, CC BY-SA 4.0.