ratchet Meaning, Definition & Usage

  1. noun mechanical device consisting of a toothed wheel or rack engaged with a pawl that permits it to move in only one direction
    rachet; ratch.
  2. verb move by degrees in one direction only
    ratchet down; rachet up.
    • a ratcheting lopping tool

WordNet

Ratch"et noun
Etymology
Properly a diminutive from the same word as rack: cf. F. rochet. See 2d Ratch, Rack the instrument.
Definitions
  1. A pawl, click, or detent, for holding or propelling a ratchet wheel, or ratch, etc.
  2. A mechanism composed of a ratchet wheel, or ratch, and pawl. See Ratchet wheel, below, and 2d Ratch. ✍ In the cut, the moving pawl c slides over the teeth in one direction, but in returning, draws the wheel with it, while the pawl d prevents it from turning in the contrary direction.

Webster 1913