Everyone knows what a duel is. A truel is a somewhat newly coined word for a duel involving three opponents.
How do you do a truel? The participants pace off approximately the same distance away from each other. They turn and shoot the other two before they are shot.
The earliest known truel may be in A. P. Herbert’s play “Fat King Melon” in 1927.
Truels have appeared in the movies too. Examples of this are “The Good, the Bad and the Ugly,” and the movie “Reservoir Dogs” where the three main characters duel each other simultaneously and only one survives.
It appears the term was not used until 1967.