The word 'trebuchet' entered English in the 14th century from the Old French 'trebuchet', itself derived from the verb 'trebucher', meaning "to overturn" or "to fall over". This verb is a compound of 'tre-', an intensive prefix, and 'bucher', meaning "to strike" or "to butt". The semantic logic is clear: the weapon's defining action is the dramatic fall of its massive counterweight, which strikes the end of the arm and overturns it, thereby hurling the projectile. Thus, the name captures the machine's core mechanism of forceful overthrow, a concept embedded in its French roots.

This word is a loanword from Old French. Its spelling and morphological structure are not productively analyzable into meaningful sub-parts in modern English.