0 a part of a machine that allows movement in one direction only. It is usually a wheel with teeth-like parts that either slide over or lock against the free end of a bar:
1 a wooden device that when turned around and around produces a noise like a series of knocks
2 something that makes a situation change or develop in one direction only, for example by being able to rise but not fall or the other way round:
4 an arrangement by which managers are given increasing numbers of shares in a company in relation to increases in its profits or success:
5 a part of a machine that allows controlled movement in one direction only
Most handbrakes need about four clicks on the ratchet -if yours takes much more, a garage should adjust it.
Catapults were loaded and cocked by means of large wheels with ratchets.
Walnut leaves have a jagged sawtooth edge rather like a ratchet.
the ratchets of a deckchair
How complex a cultural repertoire could possibly ratchet up, without primate manual dexterity?
A popular explanation holds that large green jurisdictions have been forcing their trading partners to trade or ratchet up their regulation.
We also examine the rate of the ratchet when there are two classes of mutation of similar but unequal effects on fitness.
Increased dominance also, of course, reduces the rate of the ratchet, because selection reduces the frequency of mutations even when they are heterozygous.
