overalls vs trousers

overalls

noun
  • Loose-fitting pants with supporting cross-straps and a panel of material in the chest (called a bib), often associated with farm work. 

  • A loose-fitting garment worn over regular clothes to protect them. 

  • Trousers traditionally worn by cavalry. 

trousers

noun
  • An article of clothing that covers the part of the body between the waist and the ankles or knees, and is divided into a separate part for each leg. 

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