-athlon

Etymology
From.

Suffix

 * 1) Contest

Etymology
From, largely via.

Usage notes

 * Only used in reference to biathlons and triathlons. For competitions with more than three events, compounds of a numeral and are used instead. For example, a quadrathlon is not known as a *kvadrathlon, but as a.
 * SAOL, published in 2015, recommends the spelling, but  remains the dominant form. Both are pronounced the same.