bonnet vs winter rat

bonnet

noun
  • The hinged cover over the engine of a motor car; a hood. 

  • A metallic canopy, or projection, over an opening, as a fireplace, or a cowl or hood to increase the draught of a chimney, etc. 

  • The second stomach of a ruminant. 

  • A ducat, an old Scottish coin worth 40 shillings. 

  • A roofing over the cage of a mine, to protect its occupants from objects falling down the shaft. 

  • A traditional Scottish woollen brimless cap; a bunnet. 

  • A small defence work at a salient angle; or a part of a parapet elevated to screen the other part from enfilade fire. 

  • A frame of wire netting over a locomotive chimney, to prevent escape of sparks. 

  • In pumps, a metal covering for the openings in the valve chambers. 

  • A mushroom of the genus Mycena. 

  • A type of hat, once worn by women or children, held in place by ribbons tied under the chin. 

  • The polishing head of a power buffer, often made of wool. 

  • A length of canvas attached to a fore-and-aft sail to increase the pulling power. 

verb
  • To put a bonnet on. 

winter rat

noun
  • An old, unattractive automobile, purchased for little money, to be driven during brutal Great Lakes winters while the owner's "good" car remains garaged and protected from corrosive road salt for the season. 

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