One that lays: a tile layer. A hen kept for laying eggs. A single thickness of a material covering a surface or forming an overlying part or segment: a layer of dust on the windowsill; a cake with four layers. A usually horizontal deposit or expanse; a stratum: layers of sedimentary rock; a layer of warm air. A depth or level: a poem with several layers of meaning. Botany A stem that is covered with soil for rooting while still part of the living plant. An item of clothing worn over or under another. To divide or form into layers: layered gravel and charcoal to make a filter. To cut (hair) into different, usually overlapping lengths. Botany To propagate (a plant) by means of a layer. To wear (clothing) in layers. To form or come apart as layers. Botany To take root as a result of layering.