A pawl, click or detent for holding or propelling a ratchet wheel, or ratch, etc.
A mechanism composed of a ratchet wheel, or ratch and pawl.
A ratchet wrench.
(by extension) A procedure or regulation that goes in one direction, usually up.
To cause to become incremented or decremented.
It's time to ratchet up the intensity level here.
To increment or decrement.
Ghetto; unseemly, indecorous.