ni·dus (n??d?s)n. pl. ni·dus·es or ni·di (-d?) 1. A central point or focus of infection by bacteria or other pathogens.2. A point or place at which something originates, accumulates, or develops, such as the center around which a calculus forms.[Latin n?dus; see sed- in Indo-European roots.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.nidus (?na?d?s) n, pl -di (-da?) 1. (Zoology) the nest in which insects or spiders deposit their eggs2. (Pathology) pathol a focus of infection3. (Botany) a cavity in which plant spores develop[C18: from Latin nest] ?nidal adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ni?dus (?na? d?s) n., pl. -di (-d?). 1. a nest, esp. one in which insects, spiders, etc., deposit their eggs. 2. any focal point in the body where bacteria or other infectious organisms tend to thrive. [1735?45;