af·​fine | \ a-ˈfīn How to pronounce affine (audio) , ə- \

Definition of affine

 (Entry 1 of 2)

: a relative by marriage : in-law



Definition of affine (Entry 2 of 2)

: of, relating to, or being a transformation (such as a translation, a rotation, or a uniform stretching) that carries straight lines into straight lines and parallel lines into parallel lines but may alter distance between points and angles between lines affine geometry

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Other Words from affine


affinely adverb

Examples of affine in a Sentence

Recent Examples on the Web: Noun Ruby Prosser Scully at New Scientist reports that the researchers found a species called Sphagnum affine, or bog moss, in Ötzi’s colon. Jason Daley, Smithsonian, "Mosses Expand the Story of Ötzi the Iceman’s Final Journey," 1 Nov. 2019 Recent Examples on the Web: Adjective The affine wealth model has been applied to empirical data from many countries and epochs. Bruce M. Boghosian, Scientific American, "Is Inequality Inevitable?," 1 Nov. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'affine.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of affine


circa 1509, in the meaning defined above


1896, in the meaning defined above

History and Etymology for affine


borrowed from Anglo-French affin, going back to Latin affīnis "neighbor, relation by marriage," noun derivative of affīnis "bordering (on), related by marriage" — more at affinity


borrowed from New Latin affīnis, taken to mean "having affinity," going back to Latin, "bordering (on), connected (with)" — more at affinity

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Time Traveler for affine

Time Traveler

The first known use of affine was circa 1509

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Cite this Entry

“Affine.” Dictionary, Merriam-Webster, Accessed 16 Apr. 2021.

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More Definitions for affine


af·​fine | \ a-ˈfīn, ə- How to pronounce affine (audio) \

Legal Definition of affine

: a relative by marriage — compare blood relative

Other Words from affine

affinal \ -​ˈfī-​nəl \ adjective

History and Etymology for affine

Middle French affin, from Latin affinis, from affinis related, from ad to + finis end, border

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