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

Wall Street’s artificial intelligence boom is edging toward a new milestone as one of the industry’s most valuable startups takes steps toward a potential public debut. —Aamir Khollam, Interesting Engineering, 1 June 2026

Many professionals spend years chasing the next milestone. —Bybryan Robinson, Forbes.com, 1 June 2026

That milestone at the ASCO meeting reflects the dizzying growth of China’s biotechnology sector. —Ed Silverman, STAT, 1 June 2026

Kansas City Royals starter Michael Wacha reached a career milestone against the Texas Rangers on Sunday afternoon. —Jaylon Thompson, Kansas City Star, 1 June 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