It is a triathlon
Triology
Trisection
If your racing and betting on each others horses its called Racing for Pinks!
The three secondary parts of a triangle are typically associated with one word. They are commonly called the perpendicular bisectors of the triangle.
The cerebrum, brain stem and the cerebellum.
one third = 1/3
A three part theme is another term for an essay. It is called a three part theme because of its three parts: 1. The intro 2. the Body and 3. the Conclusion.
That could be called a trilogy, although that may refer to a series of three movies. Then again, if the three "parts" of the movie are all seperate movies (eg. Harry Potter and the Deathly Hallows part 1 and 2 were seperate movies) then three parts of a movie could be called a trilogy.
The three main parts of a clock is called an energy supply, a mechanism for regulating the energy and a way of showing the passing of time
neucles , fatousmousa , gladuos wall
quartiles