Merriam-Webster Collegiate Dictionary - joust

 I. intransitive verb  Etymology: Middle English, from Anglo-French juster to unite, ~, from Vulgar Latin *juxtare, from Latin juxta near; akin to Latin jungere to join — more at yoke  Date: 14th century  1.  a. to fight on horseback as a knight or man-at-arms  b. to engage in combat with lances on horseback  2. to engage in combat or competition as if in a ~ ~ing debaters ~ing bighorn rams  • ~er noun  II. noun  Date: 14th century  1.  a. a combat on horseback between two knights with lances especially as part of a tournament  b. plural tournament  2. a personal combat or competition ; struggle