Noun

(en noun)

Something that motivates, rouses, or encourages.

* {{quote-magazine, date=2013-06-07, author=David Simpson

, volume=188, issue=26, page=36, magazine=(The Guardian Weekly) , title= Fantasy of navigation , passage=It is tempting to speculate about the incentives or compulsions that might explain why anyone would take to the skies in [the] basket [of a balloon]: perhaps out of a desire to escape the gravity of this world or to get a preview of the next; […].}}

A bonus or reward, often monetary, to work harder.

Noun

(en noun)

(chemistry) A substance that increases the rate of a chemical reaction without being consumed in the process.

* 1988 , Biochemistry , 3rd edition, page 177

Enzymes, the catalysts of biological systems, are remarkable molecular devices that determine the pattern of chemical transformations.

Someone or something that encourages progress or change.

Economic development and integration are working as a catalyst for peace.

* 1978 , Ernest George Schwiebert, Trout , Volume 2

It was a morning baptized by my first cup of coffee, freshly brewed over a gravel-bar fire, while they celebrated with the stronger catalyst of sour-mash whiskey in their fishing-vest cups.

* 2004 , Michael B. Oren, Six Days of War: June 1967 and the making of the modern Middle East , page 76

Israel's fear for the reactor—rather than Egypt's of it—was the greater catalyst for war.

* 2006 , The Freedom Writers, with Erin Gruwell, The Freedom Writers Diary: How a Teacher and 150 Teens Used Writing to Change Themselves and the World Around Them , Diary 74

Rosa Parks was a true catalyst' for change and she was only one person. Hearing about Rosa Parks and her protest showed me that there is hope for me and all the students in Ms. G's classes to truly be ' catalysts for change.

* '>citation

(literature) An inciting incident which that sets the successive conflict into motion.

(automotive) A catalytic converter.