The word 'triathlon' is a modern English formation, directly constructed from classical Greek elements to precisely describe a multi-sport event. The prefix 'tri-', derived from the Greek 'treis' (three) via Latin, clearly denotes the number of components. The core element '-athlon' originates from the Greek 'athlon', meaning "contest" or "prize for a contest", famously seen in 'decathlon' and the ancient Olympic Games. Thus, the term's literal construction as "a contest of three events" transparently and logically defines the modern athletic discipline, showcasing the enduring use of Greek roots in creating precise technical vocabulary.

Structure: tri (three) + athlon (contest) - tri: From Greek, via Latin; a combining form meaning "three". It functions as a numerical prefix. - athlon: From Greek; a combining form meaning "contest" or "prize". It functions as the core noun element.