caliber

noun

cal·​i·​ber ˈka-lə-bər 

British also kə-ˈlē-

variants or calibre

1

a

: degree of mental capacity or moral quality

teachers of high caliber

b

: degree of excellence or importance

the caliber of instruction

2

a

: the diameter of a bullet or other projectile

b

: the diameter of a bore of a gun usually expressed in hundredths or thousandths of an inch and typically written as a decimal fraction

.32 caliber

3

: the diameter of a round or cylindrical body

especially : the internal diameter of a hollow cylinder

Synonyms of caliber

• quality
• rate

Examples of caliber in a Sentence

I was impressed by the high caliber of the team's work.

musicians of the highest caliber perform at that concert hall

Recent Examples on the Web

Cuban officials say the speedboat, registered in the United States, was carrying firearms of various calibers, including 14 rifles, 11 pistols and nearly 13,000 rounds of ammunition. —CBS News, 6 Mar. 2026

Among Miami’s potential free agents at cornerback are Kader Kohou, Jack Jones, Rasul Douglas and JuJu Brents, who are all starting-caliber. —Chris Perkins, Sun Sentinel, 5 Mar. 2026

Investigators found two different caliber shell casings at the crime scene, and obtained video showing one of the shooters stand over him and fire at him as another grabbed McFee’s backpack and fled. —Nate Gartrell, Mercury News, 5 Mar. 2026

Regional American wines are a strength of this particular list, and cocktails are sensible and executed with an eye to matching the caliber of the food. —Condé Nast, Condé Nast Traveler, 4 Mar. 2026

Word History

Etymology

borrowed from Middle French calibre "internal diameter of a cylindrical object, displacement of a gun," borrowed (by uncertain mediation) from Arabic qālab, qālib "mold for casting metal, shoemaker's last," borrowed from Greek kalapod-, kalápous, kalópous "shoemaker's last," from kâla (plural) "wood, timber" (of uncertain origin) + -a- (perhaps after tetrápous "four-footed") or -o- -o- + poús "foot" — more at foot entry 1

First Known Use

1588, in the meaning defined at sense 2b

Rhymes for caliber

• excalibur

Kids Definition

caliber

noun

cal·​i·​ber

variants or calibre

ˈkal-ə-bər 

1

: degree of excellence or importance

2

: the diameter of a missile (as a bullet)

3

: the inside diameter of a gun barrel

Medical Definition

caliber

noun

cal·​i·​ber

variants or chiefly British calibre

ˈkal-ə-bər, British also kə-ˈlē-

: the diameter of a round or cylindrical body

especially : the internal diameter of a hollow cylinder