What is a cardinal?

Answer 1

The cardinality of a finite set is the number of elements in the set. The cardinality of infinite sets is infinity but - if you really want to go into it - reflects a measure of the degree of...

Answer 2

* (Roman Catholic Church) one of a group of more than 100 prominent bishops in the Sacred College who advise the Pope and elect new Popes * cardinal number: the number of elements in a mathematical set; denotes a quantity but not the order * a variable color averaging a vivid red * serving as an essential component; "a cardinal rule"; "the central cause of the problem"; "an example that was fundamental to the argument ... * crested thick-billed North American finch having bright red plumage in the male * being or denoting a numerical quantity but not order; "cardinal numbers"