(wī) noun
1. Something similar to a Y in shape.
2. A branch pipe, forked pipe, or coupling in the shape of the letter Y.
3. A forked piece, often with the branches curved, usually one of a pair, serving as a rest or support, as for some part of a sighting instrument.

—symbol Chem. Yttrium (symbol Y).

Used in Middle English as a sign of the past participle, as an intensive, or without perceptible force: yclad, yclept. It survives (as a-) in such words as alike, aware, etc. Also spelled ;i-, as in iwis. [OE ge-]