What is the meaning of Ratchet?

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.

A procedure or regulation that goes in one direction, usually up.

A noisemaker or musical instrument where sound is generated by a board striking against a rotating gear.

Ellipsis of full ratchet.

To increment or decrement; especially, to offer controlled motion that can increment while resisting decrement, or vice versa.

To cause (something) to become incremented or decremented.

Ghetto; unseemly, indecorous.

Source: wiktionary.org