gemmule vs pinion

gemmule

noun
  • Synonym of plumule (“the first bud, or growing point, of a plant embryo, situated above the cotyledons”) 

  • In the obsolete theory of pangenesis propounded by the English scientist Charles Darwin (1809–1882): a hypothetical particle once thought to be the basis of heredity. 

  • Synonym of dendritic spine (“a small membranous protrusion from the dendrite of a neuron that typically receives input from a single axon at the synapse”) 

pinion

noun
  • A moth of the genus Lithophane. 

  • The smallest gear in a gear train. 

  • Any of the outermost primary feathers on a bird's wing. 

  • The joint of a bird's wing farthest from the body. 

  • A wing. 

verb
  • To restrain; to limit. 

  • To cut off the pinion of a bird’s wing, or otherwise disable or bind its wings, in order to prevent it from flying. 

  • To bind the arms of someone, so as to deprive him of their use; to disable by so binding. 

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