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

dune \dune\ d=un, n. the same word as down: cf. d. duin.
   see down a bank of sand.
   a low hill of drifting sand usually formed on the coats, but
   often carried far inland by the prevailing winds. written
   also dun.
   1913 webster

         three great rivers, the rhine, the meuse, and the
         scheldt, had deposited their slime for ages among the
         dunes or sand banks heaved up by the ocean around their
         mouths.                                  --motley.
   1913 webster
see also:
down dun 

[2] : WordNet (r) 2.0

dune
     n : a ridge of sand created by the wind; found in deserts or
         near lakes and oceans syn: sand dune
see also:
sand dune 

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

35 moby thesaurus words for "dune":
   anthill, bank, barrow, brae, butte, cock, down, drift, drumlin,
   embankment, fell, foothills, haycock, haymow, hayrick, haystack,
   heap, hill, hillock, hummock, knob, knoll, molehill, monticle,
   monticule, moor, mound, mow, pile, pyramid, rick, sand dune,
   snowdrift, stack, swell

Dune >> D Words
Dune, definition of term: Dune
dune_pag1.html

Sand Dune >> S Words
Sand Dune, definition of term: Sand Dune
sand+dune_pag1.html