Source : Webster's Revised Unabridged Dictionary (1913)

Detour \De`tour"\, n. [F. d['e]tour, fr. d['e]tourner to turn
   aside; pref. d['e]- (L. dis-) + tourner to turn. See {Turn}.]
   A turning; a circuitous route; a deviation from a direct
   course; as, the detours of the Mississippi.

Source : WordNet®

detour
     n : a roundabout road (especially one that is used temporarily
         while a main route is blocked) [syn: {roundabout way}]
     v : travel via a detour