stratum vs venation

stratum

noun
  • A layer of tissue. 

  • One of several parallel horizontal layers of material arranged one on top of another. 

  • A layer of sedimentary rock having approximately the same composition throughout. 

  • Any of the regions of the atmosphere, such as the stratosphere, that occur as layers. 

  • A class of society composed of people with similar social, cultural, or economic status. 

  • A layer of vegetation, usually of similar height. 

  • The level of accuracy of a computer's clock, relative to others on the network. 

venation

noun
  • The arrangement of veins in a leaf, wing, or similar structure. 

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