milestone

noun

mile·​stone ˈmī(-ə)l-ˌstōn 

1

: a stone serving as a milepost (see milepost sense 1)

2

: a significant point in development

Graduating from college was an important milestone in her life.

Illustration of milestone

• milestone 1

Synonyms of milestone

• climax
• landmark
• watershed
• corner

Examples of milestone in a Sentence

the new drug was regarded as a milestone in the treatment of heart disease

Recent Examples on the Web

Developers say the bridge's removal marks a major milestone for the Portsmouth Square Improvement Project, adding 20,000 square feet of usable park space. — Maddie White, CBS News, 1 Aug. 2026

Butterfly Bash was introduced as the signature celebration of the milestone year. — Sophia Buonpane, Kansas City Star, 1 Aug. 2026

Cities and towns construct and design and the Connecticut Department of Transportation will oversee milestones and provide guidance to the municipalities receiving the grants. — Sean Krofssik, Hartford Courant, 1 Aug. 2026

The Cleveland Guardians are on the cusp of an historic 10,000th regular-season victory, a milestone only two other American League teams have reached, while simultaneously locked in a tight 10-team playoff battle for 2026. — Chuck Murr, Forbes.com, 1 Aug. 2026

Word History

First Known Use

1662, in the meaning defined at sense 1

Rhymes for milestone

• acetone
• anglophone
• baritone
• bourguignon
• buspirone
• chaperon
• chaperone
• cobblestone
• collarbone
• cornerstone
• cortisone
• dictaphone

Kids Definition

milestone

noun

mile·​stone ˈmī(ə)l-ˌstōn 

1

: a milepost made of stone

2

: an important point in progress or development