The term 'START OF A CYCLE?' can be answered by two three-letter words: TRI and UNI. TRI is short for tricycle, which is a three-wheeled vehicle typically used by children. It is the start of a cycle because it has three wheels, which is the same number of wheels as a regular bicycle. UNI is short for unicycle, which is a one-wheeled vehicle typically used by circus performers. It is the start of a cycle because it has one wheel, which is the same number of wheels as a regular bicycle.