Adjective
Growing, increasing, gaining size, etc.
Crescent-shaped.
Source: en.wiktionary.orgA crescentic dune with a star dune superimposed on its crest is the most common complex dune. Source: Internet
The broken pumice is clear and isotropic, and very small particles commonly have crescentic, sickle-shaped, or biconcave outlines, showing that they are produced by the shattering of a vesicular glass, sometimes described as ash-structure. Source: Internet
Some types of crescentic dunes move more quickly over desert surfaces than any other type of dune. Source: Internet