amnion vs sheet

amnion

noun
  • The innermost membrane of the fetal membranes of reptiles, birds, and mammals; the sac in which the embryo is suspended. 

sheet

noun
  • A layer of veneer. 

  • A piece of paper, usually rectangular, that has been prepared for writing, artwork, drafting, wrapping, manufacture of packaging (boxes, envelopes, etc.), and for other uses. The word does not include scraps and irregular small pieces destined to be recycled, used for stuffing or cushioning or paper mache, etc. 

  • A sail. 

  • A thin bed cloth used as a covering for a mattress or as a layer over the sleeper. 

  • A thin, flat layer of solid material. 

  • A line (rope) used to adjust the trim of a sail. 

  • The area of ice on which the game of curling is played. 

  • Precipitation of such quantity and force as to resemble a thin, virtually solid wall. 

  • A flat metal pan, often without raised edge, used for baking. 

  • A broad, flat expanse of a material on a surface. 

  • An extensive bed of an eruptive rock intruded between, or overlying, other strata. 

  • The space in the forward or after part of a boat where there are no rowers. 

verb
  • To form into sheets. 

  • Of rain, or other precipitation, to pour heavily. 

  • To cover or wrap with cloth, or paper, or other similar material. 

  • To trim a sail using a sheet. 

How often have the words amnion and sheet occurred in a corpus of books? (source: Google Ngram Viewer )