noun, plural car·di·nal·i·ties. Mathematics.

(of a set) the cardinal number indicating the number of elements in the set.

Origin of cardinality

First recorded in 1930–35; cardinal + -ity Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for cardinality



maths the property of possessing a cardinal number
maths logic (of a class) the cardinal number associated with the given class. Two classes have the same cardinality if they can be put in one-to-one correspondence
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for cardinality

1520s, "condition of being a cardinal," from cardinal (n.) + -ity. Mathematical sense is from 1935 (see cardinal (adj.)).

Online Etymology Dictionary, © 2010 Douglas Harper