ni·​dus ˈnī-dəs How to pronounce nidus (audio)
plural nidi ˈnī-ˌdī How to pronounce nidus (audio) or niduses
: a nest or breeding place
especially : a place or substance in an animal or plant where bacteria or other organisms lodge and multiply
: a place where something originates, develops, or is located

Did you know?

Nidus literally means "nest" in Latin, and some of its relatives in English suggest this connection in a straightforward way. For example, we have nidification for the process of building a nest, and nidicolous, meaning "reared in a nest." But nidus itself, when used as an English word, is apt to refer to a place where bacteria lodge and multiply. Consequently, the extended use of nidus in English often has a negative connotation referring to a source of undesirable opinions or behaviors.

Examples of nidus in a Sentence

a type of contact lens that proved to be a nidus of infection
Recent Examples on the Web To deliberately collapse and compress a lobe of lung, and with it, its nidus of festering infection. Rebecca Kreston, Discover Magazine, 24 Mar. 2017 The indisputably desirable goal of supporting walking, biking and bus-riding around an Uptown nidus was severely wounded. Star Tribune, 30 Nov. 2020

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'nidus.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


New Latin, from Latin

First Known Use

1734, in the meaning defined at sense 1

Time Traveler
The first known use of nidus was in 1734


Dictionary Entries Near nidus

Cite this Entry

“Nidus.” Dictionary, Merriam-Webster, Accessed 26 May. 2024.

Medical Definition


ni·​dus ˈnī-dəs How to pronounce nidus (audio)
plural nidi -ˌdī How to pronounce nidus (audio) or niduses
: a place where something originates or is fostered or develops
specifically : the point of origin or focus of an infection or disease process
Love words? Need even more definitions?

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