ini·​ti·​a·​tor in-ˈish-ē-ˌāt-ər How to pronounce initiator (audio)
: one that initiates: as
: a substance that initiates a chemical reaction
: a substance that produces an irreversible change in bodily tissue causing it to respond to other substances which promote the growth of tumors

Dictionary Entries Near initiator

Cite this Entry

“Initiator.” Medical Dictionary, Merriam-Webster, Accessed 25 Feb. 2024.

More from Merriam-Webster on initiator

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!