What is the meaning of layer?

noun

• Single thickness of usually some homogeneous substance.
  • usage: "slices of hard-boiled egg on a bed of spinach"
  • synonyms: bed
• A relatively thin sheetlike expanse or region lying over or under another.
• An abstract place usually conceived as having depth.
  • usage: "a good actor communicates on several levels"; "a simile has at least two layers of meaning"; "the mind functions on many strata simultaneously"
  • synonyms: level, stratum
• A hen that lays eggs.
• Thin structure composed of a single thickness of cells.

verb

• Make or form a layer.
  • usage: "layer the different colored sands"