English Reference

Word

billiard

Phoneticsbil·liard

US/ˈbɪɫjɝd/

UK/bˈɪlɪəd/

Definitions

01relating to the game

B2

adj. used to describe things that belong to the game of billiards.

adj. pertaining to the game of billiards; typically used as an attributive noun.

“The old hotel had a beautiful billiard room with dark wood walls.”

“The restoration of the billiard table required specialized felt and a level of precision that few local craftsmen could provide.”

Usage

Usually appears before another noun, such as 'table', 'room', or 'ball'.

02a specific shot

C1 · Sport

n. a shot in games like billiards where your ball hits two other balls.

n. a shot in which the cue ball strikes two other balls in succession; a carom.

“He won the game with a perfect billiard into the corner.”

“The player executed a difficult billiard, using the side cushion to redirect the cue ball toward the final target.”

Technical

Synonyms

carom

03math/physics system

C2 · Math

n. a math model where a particle bounces off boundaries like a ball on a table.

n. a dynamical system in which a particle alternates between straight-line motion and specular reflections from a boundary.

“The professor explained how a billiard works in a circular space.”

“In chaotic dynamics, the Sinai billiard serves as a fundamental model for studying the behavior of particles in a confined geometry.”

Technical · Academic

04a very large number

C2 · Math

num. a very old name for the number one followed by 15 zeros.

num. a thousand billion (10 to the power of 15) in the long scale system.

“In some old books, a billiard meant a thousand billion.”

“The term billiard is now largely obsolete in British mathematics, having been replaced by the short-scale quadrillion.”

Archaic · British English

Teaching tip

This sense is extremely rare and likely to confuse modern speakers; avoid using it in contemporary contexts.

Synonyms

quadrillion

Real-World Examples

“Like billiard balls striking one another on a frictionless table, they can exchange momentum without slowing the group as a whole.”
Phys.org · 16 Sept 2026

Etymology

From French billard, originally referring to the wooden cue stick, diminutive of Old French bille (“log, tree trunk”), from Vulgar Latin bilia, probably of Gaulish origin (compare Old Irish bile (“large tree, tree trunk”)), from Proto-Celtic belyos (“tree”), from Proto-Indo-European bʰolh₃yos (“leaf”), from bʰleh₃- (“blossom, flower”).

From French billiard, equivalent to bi- (“two”) + -illiard.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

billiardNounbilliardsNoun

This entry

Level
C2 · Proficiency
Frequency
Occasional
Updated

Scan code

englishreference.com/q/billiard

English Reference