Cardinal numbers

Cardinals: In mathematics, cardinal numbers, or cardinals for short, are a generalization of the natural numbers used to measure the cardinality (size) of sets.

Cardinal: The northern cardinal (Cardinalis cardinalis) is a North American bird in the genus Cardinalis; it is also known colloquially as the redbird or common cardinal. It can be found in southern Canada, through the eastern United States from Maine to Texas and south through Mexico, Belize and Guatemala. Its habitat includes woodlands, gardens, shrublands, wetlands.