Definition

1. Adjective:

   • Fundamental, of primary importance: Describes something that is most important, essential, or central.
   • Relating to number quantity: Denoting a simple numerical quantity (e.g., one, two, three) without indicating order or position.

2. Noun:

   • A high-ranking bishop in the Roman Catholic Church: A member of the Sacred College who advises the Pope and participates in electing a new Pope.
   • A North American songbird: A crested finch, the male of which has bright red plumage.
   • A vivid red color: A color resembling the red plumage of the bird.
   • A number denoting quantity: In mathematics, the number of elements in a set.

Usage Examples

• Adjective:

  • Honesty is a cardinal virtue in many cultures.
  • "One," "two," and "three" are cardinal numbers.

• Noun:

  • The Pope appointed a new cardinal from Latin America.
  • A bright red cardinal was perched on the fence.
  • She painted the door in a rich cardinal red.
  • The cardinal of the set {a, b, c} is three.

Advanced Usage

• "Cardinal sin": A very serious or fundamental error, often used figuratively outside of religious contexts.

  • Forgetting the client's name was a cardinal sin in public relations.

• "Cardinal point": One of the four main directions of the compass (north, south, east, west).

  • The ancient navigators learned to identify the cardinal points by the stars.

Variants and Related Words

• Cardinalate / Cardinalcy (n): The office, rank, or term of office of a cardinal.

  • He was elevated to the cardinalate last year.

• Cardinally (adv): In a fundamental or essential manner.

  • The two theories differ cardinally in their basic assumptions.

Synonyms

• Adjective (fundamental): Essential, primary, principal, key, paramount.
• Adjective (numerical): Quantitative.
• Noun (bird): Cardinal grosbeak, redbird.
• Noun (color): Crimson, scarlet.

Related Phrases

• Cardinal rule: A fundamental or most important rule.

  • The cardinal rule of hiking is to tell someone where you are going.

• Cardinal virtue: One of the primary moral virtues (often identified as prudence, justice, temperance, and fortitude).

  • Justice is considered a cardinal virtue.

Idioms

• Cardinal and ordinal: A phrase used together to distinguish between numbers that indicate quantity (cardinal: one, two) and numbers that indicate order or position (ordinal: first, second).
  • When learning numbers, students must understand the difference between cardinal and ordinal numbers.

Adjective

1. being or denoting a numerical quantity but not order
   • cardinal numbers
2. 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

Noun

1. crested thick-billed North American finch having bright red plumage in the male
2. a variable color averaging a vivid red
3. the number of elements in a mathematical set; denotes a quantity but not the order
4. (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