dune

a large hill of sand, especially one formed by the wind in a desert or at the seaside

duna, montículo de arena

Collocations sand dune

• The sand dunes were covered in wildflowers.

  Las dunas estaban cubiertas de flores silvestres.

a large pile of sand or earth made for a special purpose, such as to protect against flooding or to provide somewhere to walk on the beach

montículo artificial de arena o tierra

Collocations artificial dune

• The city built a large sand dune to protect the beach from erosion.

  La ciudad construyó una gran montículo de arena para proteger la playa de la erosión.