n.
Variant: also rach · et
Pronunciation: ' ra-ch ə t
Function: noun
Etymology: alteration of earlier rochet, from F, alteration of Middle French rocquet ratchet, bobbin, of Germanic origin; akin to Old High German rocko distaff ― more at ROCK
Date: 1654
1 : a mechanism that consists of a bar or wheel having inclined teeth into which a pawl drops so that motion can be imparted to the wheel or bar, governed, or prevented and that is used in a hand tool (as a wrench or screwdriver) to allow effective motion in one direction only
2 : a pawl or detent for holding or propelling a toothed wheel