Enzyme
Etymology
From Greek "en" (in) plus "zyme" (leaven, yeast), coined by Wilhelm Kühne in 1877 because the first known examples worked like the ferment in rising dough.
noun · /EN-zime/
A protein that speeds up a specific chemical reaction in a living thing without being used up.
What it names
Life’s toolkit of biological catalysts — the molecules that let reactions which would take years happen in a fraction of a second at body temperature.
Example
The enzymes in your saliva start breaking down starch into sugar before you even swallow.
Related idea
An enzyme is a catalyst, but a biological and highly selective one: where an industrial catalyst may speed many reactions, each enzyme is shaped to fit one particular molecule, like a key to a single lock.
See also