A Grammatical Dictionary of Botanical Latin

Sandbar, sandbank, offshore bar, shoal; a submerged or partly exposed (emergent) ridge of silt, sand or coarse sediment that is built by waves offshore from a beach: arena,-ae (s.f.I), q.v.; syrtis,-idos (s.f.III), a sandbank in the sea; 'of the sandbanks on the coast of Africa, of which there were two, the Syrtis Major and Minor' (Liddell & Scott); thinium,-ii (s.n.II), q.v., abl. sg. thinio, dat. & abl. pl. thiniis: a sand dune [> Gk. ‘this’ [theta,-i,-s], gen. sg. thinos (s.m. and f. III), a heap, esp. of sandbanks; sandbank, sandbar, at the mouth of a river; the banks of a stream; sand or mud at the bottom of the sea (Liddell & Scott); a heap of sand on the beach, a dune + -ion, diminutive]; see sand dune.

Flat (Eng.noun): “a level tract lying at little depth below the surface of water or alternately covered and left bare by the tide: shoal, shallow [Eng.noun], strand; also a tract of wet low-lying level land: marsh, swamp” (WIII).