the world > the earth > land > landscape > high land > rising ground or eminence > [noun] > undulation > sand-wave (3)
a wave-like formation in sand; spec. in Physical Geography, an undulation similar to a megaripple but on a larger scale.
one of a series of small parallel ridges or undulations in the surface of sand.
an extensive undulation of the surface of a sandy beach or sea bed, that is typically tens of metres from crest to crest and tens of centimetres in…