lamina vs trackbed

lamina

noun
  • a fine layer that occurs in sedimentary rocks 

  • the flat expanded part of a foliage leaf or leaflet 

  • either of two broad, flat plates of bone of a vertebra that is fused with and extends from the pedicle to the median line of the neural arch to form the base of the spinous process and that along with the pedicle forms the posterior part of the vertebral foramen 

  • one of the narrow thin parallel plates of soft vascular sensitive tissue that cover the flesh within the wall of a hoof 

trackbed

noun
  • The layer of gravel or other foundation on which a railway track is laid. 

  • The land on which a railway (especially one that has been closed or dismantled) was built; the roadbed for a railroad. 

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