: a number (such as 1, 5, 15) that is used in simple counting and that indicates how many elements there are in an assemblage see Table of Numbers
2
: the property that a mathematical set has in common with all sets that can be put in one-to-one correspondence with it
Example Sentences
Recent Examples on the WebThe result means both axioms are more likely to be true, which in turn suggests that the number of real numbers is bigger than initially thought, corresponding to the cardinal number rather than the smaller (yet still infinite) .Quanta Magazine, 23 Dec. 2021 The cardinal number 𝔡 is defined as the smallest possible size of a set of continuous functions sufficient to dominate every possible continuous function. Martin Goldstern, Scientific American, 16 Aug. 2021 With the hypothesis unresolved, many other properties of cardinal numbers and infinity remain uncertain too.Quanta Magazine, 26 Nov. 2013