Question: what are words that start with the prefix tri?
Answer: triathlon (n) a race that combines three activities-swimming, bycycling, & running.
triceratops (n) a dinosaur with 3 horns-two long horns above the eyes and one short horn on the nose. ... 
tricycle (n) ... 
trilateral (adj) ... 
trilingual (adj) ... 
trilogy (n) ... 
trio (n) ... 
tripod (n)