Origin: Latin suffix -al
Cardinal has 9 different meanings across 2 categories:
(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
"After years of serving as an advisor to the Holy See, the cardinal was finally elected by his peers to succeed the late Pope."
the number of elements in a mathematical set; denotes a quantity but not the order
"The cardinality of this finite set is five, indicating that there are exactly five distinct members without regard to their sequence."
crested thick-billed North American finch having bright red plumage in the male
"The male cardinal perched on the feeder, its brilliant red feathers contrasting sharply against the gray winter sky."
One of the officials appointed by the pope in the Roman Catholic Church, ranking only below the pope and the patriarchs, constituting the special college which elects the pope. (See Wikipedia article on Catholic cardinals.)
"The stadium announcer urged every cardinal to take their seats before kickoff."
A player on the St. Louis Cardinals team.
In plain English: A cardinal is an orange-red bird with black wings and face that people often see during springtime.
"The cardinal perched on the fence post and chirped loudly in the morning sun."
serving as an essential component
"a cardinal rule"
"the central cause of the problem"
"an example that was fundamental to the argument"
"computers are fundamental to modern industrial structure"
Of fundamental importance; crucial, pivotal.
"The cardinal rule in any relationship is to always communicate honestly."
In plain English: Cardinal means extremely important, serious, or fundamental to something else.
"The cardinal bird has bright red feathers that stand out against the green leaves."
Usage: Use cardinal to describe something that is absolutely essential or of primary importance, such as a cardinal rule or a cardinal feature. This adjective emphasizes centrality rather than numerical value when distinguishing it from similar terms like "major."
The word comes from the Latin cardinalis, meaning "pertaining to a hinge." It originally described something important or principal because it was seen as the part on which everything turns or depends.