Tri
A three wheeled cycle.
Tricycle
Triangle
Quad means
Four
Quint means
Five
Pent means
Five
A spear or weapon with three prongs
Trident
A group of four people
Quartet
One of four parts of a shape or area.
Quadrant
A group of five people.
Quintet
A polygon with five angles and five sides.
Pentagon
A series of three related things.
Trilogy
A group of three closely related things.
Triad
A race that includes three different sporting events.
Triathlon