## Definitions

### from The American Heritage® Dictionary of the English Language, 4th Edition

• adj. Consisting of four parts or members.
• adj. Four times as much in size, strength, number, or amount.
• adj. Music Having four beats to the measure.
• n. A fourfold amount or number.
• transitive v. To multiply or be multiplied by four: quadrupled the order; quadrupled in size.

### from Wiktionary, Creative Commons Attribution/Share-Alike License

• adj. Being four times as long, as big or as many of something.
• v. To multiply something by four times.

### from the GNU version of the Collaborative International Dictionary of English

• n. four times the sum or number; a fourfold amount.
• transitive v. To multiply by four; to increase fourfold; to double; to double twice.
• intransitive v. To be multiplied by four; to increase fourfold; to become four times as much.

### from The Century Dictionary and Cyclopedia

• Fourfold; four times told.
• n. A number, sum, etc., four times as great as that taken as the standard: as, to receive the quadruple of a given sum.
• To make four times as much or as many; multiply by four; repeat four times; make, do, or cause to happen four times over.
• To become four times as much or as many; repeat itself four times.
• Consisting of four parts; completed in four separate or successive operations.

• v. increase fourfold
• adj. having four units or components
• n. a quantity that is four times as great as another
• n. a set of four similar things considered as a unit
• adj. four times as great or many

## Etymologies

From Middle English quadriple, fourfold amount, and quadruple, tooth with four roots, both from Old French quadruple, from Latin quadruplum, from neuter of quadruplus, fourfold : quadru-, quadri-, quadri- + -plus, -fold.
(American Heritage® Dictionary of the English Language, Fourth Edition)