oval vs yolk

oval

noun
  • An elongated round shape resembling an egg or ellipse. 

  • A thing having such a shape, such as an arena. 

  • In a projective plane, a set of points such that no three are collinear and there is a unique tangent line at each point. 

  • A sports field, typically but not exclusively oval in shape. 

adj
  • Of or pertaining to an ovum. 

  • Having the shape of an oval. 

yolk

noun
  • The yellow, spherical part of an egg that is surrounded by the white albumen, and serves as nutriment for the growing young. 

  • The grease in a sheep's fleece; lanolin. 

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