infinity

noun

in·​fin·​i·​ty in-ˈfi-nə-tē 

plural infinities

1

a

: the quality of being infinite

b

: unlimited extent of time, space, or quantity : boundlessness

The view tapers off into infinity.

2

: an indefinitely great number or amount

an infinity of stars

3

a

: the limit of the value of a function or variable when it tends to become numerically larger than any preassigned finite number

b

: a part of a geometric magnitude that lies beyond any part whose distance from a given reference position is finite

Do parallel lines ever meet if they extend to infinity?

c

: a transfinite number (such as aleph-null)

4

: a distance so great that the rays of light from a point source at that distance may be regarded as parallel

Synonyms of infinity

• perpetuity
• eternity

Examples of infinity in a Sentence

The view tapers off into infinity.

a series of numbers that continues to infinity

The night sky was filled with an infinity of stars.

Recent Examples on the Web

There was a picture of an infinity [sign] on the wall from the music-video thing. —Larisha Paul, Rolling Stone, 30 Apr. 2026

But if those experiments proved the opposite — that infinity does exist in nature — the ultrafinitist would have far less room to negotiate. —Quanta Magazine, 29 Apr. 2026

The Swedish Academy has simply added a new twist to a decades-long game of peekaboo, where Dylan, né Robert Zimmerman, peels back one mask to reveal another, an infinity of disguises. —New York Times, 28 Apr. 2026

All residents have access to such resort-like perks as an infinity-edge pool, meditation garden, clubhouse with bar, cinema-style screening room and spa/fitness center. —Madeleine Marr, Miami Herald, 27 Apr. 2026

Word History

Etymology

Middle English infinite, borrowed from Anglo-French infinité, borrowed from Latin infīnitāt-, infīnitās, from in- in- entry 1 + fīnis "boundary, limit, terminal point, ending" + -itāt-, -itās -ity — more at final entry 1

First Known Use

14th century, in the meaning defined at sense 1a

Phrases Containing infinity

• infinity pool
• infinity scarf

Rhymes for infinity

• affinity
• divinity
• salinity
• vicinity
• virginity
• alkalinity
• consanguinity
• crystallinity
• femininity
• masculinity

Kids Definition

infinity

noun

in·​fin·​i·​ty in-ˈfin-ət-ē 

plural infinities

1

a

: the quality of being infinite

b

: a space, quantity, or period of time that is without limit

2

: an indefinitely great number or amount

3

: a point infinitely far away

Etymology

Middle English infinite "the quality of having no limit," from early French infinité (same meaning), derived from Latin infinitus (adjective) "having no limit," from in- "not" and finitus, past participle of finire "to limit, bring to an end," from finis "end, limit" — related to define, final, finish