Word of the Day:

1 : a nest or breeding place; especially : a place or substance in an animal or plant where bacteria or other organisms lodge and multiply

2 : a place where something originates, develops, or is located

The neighborhood had long been a nidus of crime and vice, but community policing and other interventions have done much to reduce the crime rate in recent years.

"Ancient cities grew up along navigable rivers—think Cairo, Rome, Paris and London. In the 19th century, railroad stations were the nidus for Chicago, Denver, and Sacramento." — Alison Stuebe, The News & Observer (Raleigh, North Carolina), 20 Mar. 2017

More example sentences

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.