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

David Hoagland, acting deputy administrator for Defense Programs, said the CSA milestone shows that reforms intended to streamline design and manufacturing are starting to pay off. —Kapil Kajal, Interesting Engineering, 25 Nov. 2025

California’s high-speed rail project is moving into a pivotal phase, with the state’s High-Speed Rail Authority outlining its anticipated 2026 milestones during the Board of Directors meeting on November 20. —Ben Kelly, MSNBC Newsweek, 25 Nov. 2025

Doha marks the film’s Middle East and North Africa premiere, a milestone Jihan describes as emotional and overdue. —Essie Assibu, Variety, 24 Nov. 2025

Until then, the deepening of ties between Saudi Arabia and the US will provide plenty of milestones, in both countries, to celebrate. —Faisal J. Abbas, semafor.com, 24 Nov. 2025

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