layer

layer
noun [Middle English leier, from Old English leger — a bed or place of lying]

1. A hen kept for the purpose of laying eggs.
     Selected and bred for productivity, a layer is valued not for her meat but for her consistent output—often confined, monitored, and measured by performance.
     e.g., The farm's best layer produced an egg nearly every day.

2. (By extension) Any bird, particularly a chicken, that lays eggs regularly.

3. (Figurative) One who or that which places, arranges, or builds up material in levels or strata—used metaphorically in discussions of process, construction, or meaning.
     e.g., The artist is a layer of meanings, not just images.