Source : Webster's Revised Unabridged Dictionary (1913)

Devoir \De*voir"\, n. [F., fr. L. debere to owe. See {Due}.]
   Duty; service owed; hence, due act of civility or respect; --
   now usually in the plural; as, they paid their devoirs to the
   ladies. ``Do now your devoid, young knights!'' --Chaucer.

Source : WordNet®

devoir
     n : formal expression of respect