ground zero

noun

1

: the point directly above, below, or at which a nuclear explosion occurs

2

: the center or origin of rapid, intense, or violent activity or change

broadly : center sense 2a

the party town that served as ground zero for those corporate … bashes

—Rich Eisen

3

: the very beginning : square one

Synonyms

• axis
• base
• capital
• center
• central
• core
• cynosure
• epicenter
• eye
• focus
• heart
• hub
• locus
• mecca
• navel
• nerve center
• nexus
• nucleus
• omphalos
• seat

Examples of ground zero in a Sentence

ground zero in the battle over immigration laws

a city that was once ground zero for the insurance industry

Recent Examples on the Web

Today, Cicero remains ground zero as the most vulnerable town in Illinois during immigration raids. —Esteban Rodriguez, Chicago Tribune, 30 Jan. 2025

Trump officials have designated Chicago as ground zero for deportations. —Axios, 23 Jan. 2025

Incinerated communities California is America’s wildfire ground zero. —Laura Paddison, CNN, 21 Jan. 2025

On February 2, 2017, UC Berkeley became ground zero when provocateur Milo Yiannopoulos’ speech was protested- these violent protests were only the tip of the iceberg in a rapid shift in norms on college campuses. —Manu Meel, Forbes, 21 Jan. 2025

Word History

First Known Use

1946, in the meaning defined at sense 1

Kids Definition

ground zero

noun

1

: the site of a nuclear explosion

2

: the center of rapid, intense, or violent activity or change

3

: the very beginning : square one