fidelity

noun

fi·​del·​i·​ty fə-ˈde-lə-tē 

fī-

plural fidelities

1

a

: the quality or state of being faithful

fidelity to your spouse

swore fidelity to the U.S. Constitution

Did the FBI lose its reputation for fidelity to law … and integrity at all times?

—Andrew P. Napolitano

… the delicate task facing a church that needs to preserve its unity and its fidelity to tradition while honoring diversity within the institution …

—John Garvey

b

: accuracy in details : exactness

Of course, a lack of fidelity to the original is no sin—many viewers won't have read the books …

—Kate Taylor

2

: the degree to which an electronic device or a software application accurately reproduces an effect (such as sound or picture)

a printer with outstanding color fidelity

The best speakers come from quality brands known for their sound fidelity.

—Lauren Corona

… in-game settings that prioritize frame rate or visual fidelity …

—Levi Winslow

Today, the phones in our pockets can produce images with the kind of fidelity that can rival—and sometimes beat!—dedicated cameras.

—Chris Velazco

see also high fidelity

Did you know?

Have a Little Faith in Fidelity

Fidelity came to English by way of Middle French in the 15th century, and can ultimately be traced back to the Latin adjective fidēlis, meaning “faithful, loyal, trustworthy.” While fidelity was originally exclusively about loyalty, it has for centuries also been used to refer to accuracy, as in “questions about the fidelity of the translation.” Nowadays fidelity is often used in reference to recording and broadcast devices, conveying the idea that a broadcast or recording is “faithful” to the live sound or picture that it reproduces.

Synonyms of fidelity

• loyalty
• allegiance
• commitment
• dedication
• devotion

Choose the Right Synonym for fidelity

fidelity, allegiance, fealty, loyalty, devotion, piety mean faithfulness to something to which one is bound by pledge or duty.

fidelity implies strict and continuing faithfulness to an obligation, trust, or duty.

marital fidelity

allegiance suggests an adherence like that of citizens to their country.

pledging allegiance

fealty implies a fidelity acknowledged by the individual and as compelling as a sworn vow.

fealty to the truth

loyalty implies a faithfulness that is steadfast in the face of any temptation to renounce, desert, or betray.

valued the loyalty of his friends

devotion stresses zeal and service amounting to self-dedication.

a painter's devotion to her art

piety stresses fidelity to obligations regarded as natural and fundamental.

filial piety

Examples of fidelity in a Sentence

Yet as Reardon emphasizes early on, fidelity to facts was never the point. The same dinner with friends could appear over and over in Fisher's published work, rejiggered each time to make a different point. —Laura Shapiro, New York Times Book Review, 12 Dec. 2004

It is a world familiar to all children, and it is this fidelity to child life that gives resonance to Hoffmann's tale and makes it an extraordinary work of art. —Maurice Sendak, Caldecott & Co., 1988

Chaucer's patient Griselda proved her fidelity to her husband by resisting the prodigious reasons he gave her for being unfaithful. —B. F. Skinner, Beyond Freedom and Dignity, 1971

music with much higher fidelity than on cassettes

they have never wavered in their fidelity to the cause of freedom

Recent Examples on the Web

The cyber-pet also features a high-fidelity facial screen capable of thousands of expressions and concise text replies. —Mrigakshi Dixit, Interesting Engineering, 7 Jan. 2026

The threadbare ballads from ’90s indie rock records that could have been breakthrough hits if presented in slightly cleaner fidelity. —Sam Sodomsky, Pitchfork, 7 Jan. 2026

Whatever the picture size, AWOL says that its PixelLock technology guarantees 4K fidelity. —New Atlas, 5 Jan. 2026

Smaller models simulate long-range approaches, while larger, high-fidelity replicas like the one shown are used to test the most delicate, close-range phases of a rendezvous. —Kenna Hughes-Castleberry, Space.com, 30 Dec. 2025

Word History

Etymology

Middle English fidelite, borrowed from Middle French fidelité, borrowed from Latin fidēlitāt-, fidēlitās, from fidēlis "faithful, loyal, trustworthy" (from fidē-, stem of fidēs "trust, belief, faith" + -lis, denominal suffix of appurtenance) + -itāt-, -itās -ity — more at faith entry 1

First Known Use

15th century, in the meaning defined at sense 1a

Phrases Containing fidelity

• high fidelity

Rhymes for fidelity

• infidelity

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Kids Definition

fidelity

noun

fi·​del·​i·​ty fə-ˈdel-ət-ē 

fī-

plural fidelities

1

a

: the quality or state of being faithful

b

: exactness in details

2

: the degree to which an electronic device (as a record player, radio, or television) correctly reproduces its effect (as sound or a picture)

Legal Definition

fidelity

noun

fi·​del·​i·​ty fə-ˈde-lə-tē, fī- 

: the quality or state of being faithful or loyal

especially : loyalty to one's spouse in refraining from adultery and sometimes in submitting to a spouse's reasonable sexual desires