Dune Shadow

Dune

A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat regions covered with wind-swept sand or dunes, with little or no vegetation, are called ergs or sand seas. Dunes occur in different shapes and sizes, but most kinds of dunes are longer on the stoss (upflow) side, where the sand is pushed up the dune, and have a shorter slip face in the lee side. The valley or trough between dunes is called a dune slack.

Shadow

A shadow is a dark area on a surface where light from a light source is blocked by an object. In contrast, shade occupies the three-dimensional volume behind an object with light in front of it. The cross-section of a shadow is a two-dimensional silhouette, or a reverse projection of the object blocking the light.

dune

Noun

1. A ridge or hill of sand piled up by currents of wind or water.

shadow

Noun

1. A dark image projected onto a surface where light (or other radiation) is blocked by the shade of an object.
2. Relative darkness, especially as caused by the interruption of light; gloom; obscurity.

Adjective

1. Unofficial, informal, unauthorized, but acting as though it were.
2. Having power or influence, but not widely known or recognized.