Definition of "catalyst"

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

1988, Lubert Stryer, Biochemistry, 3rd edition, page 177

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.

1978, Ernest George Schwiebert, Trout, volume 2

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

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

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.

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

He [countertenor Anthony Roth Constanzo] also enjoys being the catalyst whereby opera fertilises other art forms: recently, he's collaborated with Japanese kabuki actors, and a project with dancers from New York City Ballet is in the offing.

2014 August 8, Rupert Christiansen, “The truth about falsettos ”, in The Daily Telegraph (Review)‎

The catalyst was the introduction of the Health & Safety at Work Act in 1974. While it applied to all workplaces, it gradually brought about a sea change in the attitude towards death and injury. Accidents were no longer accepted as 'inevitable'.

2022 January 26, John Crosse, “When the tide turned to a safer railway...”, in RAIL, number 949, page 53

The housing crisis is now a “catalyst” for anti-immigrant sentiment, an Irish parliamentary committee warned in November.

2023 December 11, Rory Hearne, “Ireland’s housing crisis is a disaster for its people – and a gift to far-right fearmongers”, in The Guardian‎

The current view by both Labour and Conservative politicians is that the state of the UK railway is unsustainable, and the pandemic acted as a catalyst in exposing its weaknesses.

2023 May 31, Tammy Samuel, Fergus McLaverty, “The political picture: what lies ahead for Britain's railways?”, in RAIL, number 984, page 31