This is the 5614th most frequent Catalan word.
duna
A "duna" is a "sand dune."
In this sentence, 'dunes' refers to the natural formations of sand created by wind, typically found in deserts.
Els camells travessen les dunes del desert.
The camels cross the dunes of the desert.
Here, 'dunes' describes small accumulations of sand created by natural forces, in this case, on a beach.
La sorra banyada del matí formava petites dunes a la platja.
The damp morning sand formed small dunes on the beach.
In this usage, 'dunes' are the specific natural landforms being addressed in the context of ecological study.