An Etymological Dictionary of Astronomy and Astrophysics

A thickness of some material laid on or spread over a surface.

Etymology (EN): From M.E. leyer, legger + -er. The first element from layen, leggen “to lay,” from O.E. lecgan;
cf. Du. leggen; Ger. legen; O.N. legja; Goth. lagjan

Etymology (PE): Lâyé “layer,” from lâ, lây “fold” + -é nuance suffix of nouns.