excitation vs reflex

excitation

noun
  • The activity produced in an organ, tissue, or part, such as a nerve cell, as a result of stimulation 

  • The act of exciting or putting in motion; the act of rousing up or awakening. 

  • The act of producing excitement (stimulation); also, the excitement produced. 

  • A transition of a nucleus, atom or molecule to an excited state by the absorption of a quantum of energy; the opposite of relaxation 

reflex

noun
  • An automatic response to a simple stimulus which does not require mental processing. 

  • The ancestor word corresponding to a descendant. 

  • The descendant of an earlier language element, such as a word or phoneme, in a daughter language. 

  • The descendant of anything from an earlier time, such as a cultural myth. 

  • Reflection or an image produced by reflection. The light reflected from an illuminated surface to one in shade. 

adj
  • Having greater than 180 degrees but less than 360 degrees. 

  • Illuminated by light reflected from another part of the same picture. 

  • Produced automatically by a stimulus. 

  • Bent, turned back or reflected. 

verb
  • To bend back or turn back over itself. 

  • To respond to a stimulus. 

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