pack horse vs pony

pack horse

noun
  • A horse used for carrying luggage. 

pony

noun
  • A small horse; specifically, any of several small breeds of horse under 14.2 hands at the withers. 

  • One horsepower. 

  • A translation used as a study aid; loosely, a crib, a cheat-sheet. 

  • a contraption built like a mount, strong enough to support one's weight 

  • Crap; rubbish, nonsense. 

  • A ponytail hairstyle. 

  • A small serving of an alcoholic beverage, especially beer. 

  • A serving of 140 millilitres of beer (formerly 5 fl oz); a quarter pint. 

  • Twenty-five pounds sterling. 

  • A chorus girl of small stature. 

verb
  • To lead (a horse) from another horse. 

  • To use a crib or cheat-sheet in translating. 

adj
  • Of little worth. 

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