This article is from the Triathlon FAQ, by with numerous contributions by James Goddard others.
A biathlon/duathlon is an athletic contest in which participants
compete two (or three) events in succession. Usually these events are
bicycling and running. Basically a biathlon/duathlon is a triathlon
without the swimming. The general distinction between a biathlon and a
duathlon is that a duathlons often split up the run so as to be a