The Quenya word for bow (weapon) is quinga.
The Sindarin word for bow (weapon) is peng.
I was careful translating the word bow to elven. Bow is one of those English words with multiple, diverse meanings. In addition to being a piece of resilient wood with taut cord used to shoot arrows, a bow can be the forward part of a vessel, a bending of the body as a sign of respect or acknowledgement or submission, a decorative interlacing of ribbons, and something curved in shape.