Source : Webster's Revised Unabridged Dictionary (1913)

Roost \Roost\, v. t.
   See {Roust}, v. t.

Roost \Roost\, n.
   Roast. [Obs.] --Chaucer.

Roost \Roost\, n. [AS. hr[=o]st; akin to OD. roest roost,
   roesten to roost, and probably to E. roof. Cf. {Roof}.]
   1. The pole or other support on which fowls rest at night; a
      perch.

            He clapped his wings upon his roost.  --Dryden.

   2. A collection of fowls roosting together.

   {At roost}, on a perch or roost; hence, retired to rest.

Roost \Roost\, v. i. [imp. & p. p. {Roosted}; p. pr. & vb. n.
   {Roosting}.]
   1. To sit, rest, or sleep, as fowls on a pole, limb of a
      tree, etc.; to perch. --Wordsworth.

   2. Fig.; To lodge; to rest; to sleep.

            O, let me where thy roof my soul hath hid, O, let me
            roost and nestle there.               --Herbert.

Source : WordNet®

roost
     n 1: a shelter with perches for fowl or other birds
     2: a perch on which domestic fowl rest or sleep
     v 1: sit, as on a branch; "The birds perched high in the treee"
          [syn: {perch}, {rest}]
     2: settle down or stay, as if on a roost