Twixt means between, in poetic use. Twixt sea and sky, twixt the two, betwixt and between.
It is a shortening of betwixt and it survives almost only in verse and in the phrase betwixt and between, meaning in an unsatisfactory middle position. It is usually written with an apostrophe in older printing. Note that betwixt and between are the same old word twice, from a root meaning two.
1prepositiontwixtBetween.
“The little cottage stood twixt the river and the wood.”
twixt is a preposition of place.
Middle English twix is a shortening of betwixt, from Old English betweox, from a root meaning two. Between comes from the same two.
Proto-Indo-European
*dwóh₁
Middle English
tuix
English, today
twixt
Built from
From Middle English tuix, twyx (“among; between”) + English -t. Tuix, twyx is an form of atwix, atwixen, atwixt (“between”), or bitwix, bitwixe, bitwixen, bitwixt (“among; between”):
Etymology from Wiktionary, CC BY-SA
Practised in A Song of Ice and Fire