The story
- Old English · inherited fromtwēonlēoht“twilight”
- English todaytweenlight
From Old English twēonlēoht (“twilight”, literally “double-/doubtful-/uncertain-light”). The alternative spellings are due to a misassociation with between, erroneously interpreting tweenlight as if it were a shortening of between-light.
Etymology from Wiktionary, CC BY-SA 4.0.