"figure consisting of three branches radiating from a center," 1880, earlier triskelos (1857), from Greek triskeles "three-legged," from tri- "three" (see tri-) + skelos "leg" (see scoliosis).
trireme
Triscuit
trisect
trisexual
triskaidekaphobia
triskelion
trismus
trisomy
trist
Tristram
trite