Partly from two, and partly from an alteration (due to two) of twi- (“two-, double-, in two”), from Middle English twi-, from Old English twi- (“two-”). More at twi-.
- two; double; bi-
- two-edged, two-faced, two-headed, two-tongued, two-way
- in two; by two; partially or halfway
- two-blocks, two-cleft, two-forked, two-parted