aeroplane vs airfoil

aeroplane

noun
  • Synonym of airplane. A powered heavier-than-air aircraft with fixed wings. 

  • Any of various nymphalid butterflies, of various genera, having a slow gliding flight. Also called planes. 

verb
  • To fly in an aeroplane. 

  • To transport by aeroplane. 

airfoil

noun
  • A wing of an aircraft. 

  • A structure shaped to produce lift when moving in air. 

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