[1] : The Collaborative International Dictionary of English v.0.48

retain \retain"\ r-et=an", v. t. imp.  p. p.
   retained r-et=and"; p. pr.  vb. n. retaining.
   f. retainir, l. retinere; pref. re- re- + tenere to hold,
   keep. see tenable, and cf. rein of a bridle, retention,
   retinue.
   1. to continue to hold; to keep in possession; not to lose,
      part with, or dismiss; to restrain from departure, escape,
      or the like. "thy shape invisible retain." --shak.
      1913 webster

            be obedient, and retain
            unalterably firm his love entire.     --milton.
      1913 webster

            an executor may retain a debt due to him from the
            testator.                             --blackstone.
      1913 webster

   2. to keep in pay; to employ by a preliminary fee paid; to
      hire; to engage; as, to retain a counselor.
      1913 webster

            a benedictine convent has now retained the most
            learned father of their order to write in its
            defense.                              --addison.
      1913 webster

   3. to restrain; to prevent. obs. --sir w. temple.
      1913 webster

   retaining wall arch.  engin., a wall built to keep any
      movable backing, or a bank of sand or earth, in its place;
      -- called also retain wall.
      1913 webster

   syn: to keep; hold; restrain. see keep.
        1913 webster
see also:
retained retaining tenable rein retention retinue 
retaining wall retain wall keep 

[2] : WordNet (r) 2.0

retaining wall
     n : a wall that is built to resist lateral pressure especially
         a wall built to prevent the advance of a mass of earth

[3] : Moby Thesaurus II by Grady Ward, 1.0

21 moby thesaurus words for "retaining wall":
   abutment, arc-boutant, bank, beam, breakwater, bulwark, buttress,
   buttress pier, buttressing, embankment, flying buttress, groin,
   hanging buttress, jetty, jutty, mole, pier, pier buttress, rampart,
   seawall, shoulder

Retaining Wall >> R Words
Retaining Wall, definition of term: Retaining Wall
retaining+wall_pag1.html

Retaining >> R Words
Retaining, definition of term: Retaining
retaining_pag1.html

Wailing Wall >> W Words
Wailing Wall, definition of term: Wailing Wall
wailing+wall_pag1.html

Sea Wall >> S Words
Sea Wall, definition of term: Sea Wall
sea+wall_pag1.html

Fire Wall >> F Words
Fire Wall, definition of term: Fire Wall
fire+wall_pag1.html

Chinese Wall >> C Words
Chinese Wall, definition of term: Chinese Wall
chinese+wall_pag1.html

Dead Wall >> D Words
Dead Wall, definition of term: Dead Wall
dead+wall_pag1.html

Dry Wall >> D Words
Dry Wall, definition of term: Dry Wall
dry+wall_pag1.html

Cell Wall >> C Words
Cell Wall, definition of term: Cell Wall
cell+wall_pag1.html

Great Wall Of C >> G Words
Great Wall Of C, definition of term: Great Wall Of C
great+wall+of+c_pag1.html