tribrach

noun

1. (prosody) A metrical foot consisting of three short syllables.

2. A figure or object having three arms or branches.

3. (archaeology) A tribrachial prehistoric flint implement.

4. (The addition of quotations indicative of this usage is being sought): (surveying) A circular platform on three legs, each having levelling screws, used to connect a theodolite to a tripod.