headlight vs optic

headlight

noun
  • A bright light, with a lens and reflector, on the front of a motor vehicle (or originally a ship or train), designed to illuminate the road when driving at night; normally one of a pair. 

  • A woman's breast. 

  • A jewel; especially a diamond. 

  • Lysergic acid diethylamide (LSD). 

  • A woman's erect nipples, partially masked by clothing. 

optic

noun
  • A lens or other part of an optical instrument that interacts with light. 

  • A measuring device with a small window, attached to an upside-down bottle, used to dispense alcoholic drinks in a bar. 

adj
  • Of, or relating to the eye or to vision. 

  • Of, or relating to optics or optical instruments. 

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