Source : Webster's Revised Unabridged Dictionary (1913)

Hip \Hip\, n. [OE. hipe, huppe, AS. hype; akin to D. heup, OHG.
   huf, G. h["u]fte, Dan. hofte, Sw. h["o]ft, Goth. hups; cf.
   Icel. huppr, and also Gr. ? the hollow above the hips of
   cattle, and Lith. kumpis ham.]
   1. The projecting region of the lateral parts of one side of
      the pelvis and the hip joint; the haunch; the huckle.

   2. (Arch.) The external angle formed by the meeting of two
      sloping sides or skirts of a roof, which have their wall
      plates running in different directions.

   3. (Engin) In a bridge truss, the place where an inclined end
      post meets the top chord. --Waddell.

   {Hip bone} (Anat.), the innominate bone; -- called also
      {haunch bone} and {huckle bone}.

   {Hip girdle} (Anat.), the pelvic girdle.

   {Hip joint} (Anat.), the articulation between the thigh bone
      and hip bone.

   {Hip knob} (Arch.), a finial, ball, or other ornament at the
      intersection of the hip rafters and the ridge.

   {Hip molding} (Arch.), a molding on the hip of a roof,
      covering the hip joint of the slating or other roofing.

   {Hip rafter} (Arch.), the rafter extending from the wall
      plate to the ridge in the angle of a hip roof.

   {Hip roof}, {Hipped roof} (Arch.), a roof having sloping ends
      and sloping sides. See {Hip}, n., 2., and {Hip}, v. t., 3.
      

   {Hip tile}, a tile made to cover the hip of a roof.

   {To catch upon the hip}, or {To have on the hip}, to have or
      get the advantage of; -- a figure probably derived from
      wresting. --Shak.

   {To smite hip and thigh}, to overthrow completely; to defeat
      utterly. --Judg. xv. 8.

Source : WordNet®

hip roof
     n : a roof having sloping ends as well as sloping sides