Source : Webster's Revised Unabridged Dictionary (1913)

Lieu \Lieu\ (l[=u]), n. [F., OF. also liu, leu, lou, fr. L.
   locus place. See {Local}, {Locus}.]
   Place; room; stead; -- used only in the phrase in lieu of,
   that is, instead of.

         The plan of extortion had been adopted in lieu of the
         scheme of confiscation.                  --Burke.

Source : WordNet®

lieu
     n : the function or position properly or customarily occupied or
         served by another; "can you go in my stead?"; "took his
         place"; "in lieu of" [syn: {stead}, {position}, {place}]