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

The trans-Pacific flight that took place over a month between August and September 2026 was the most notable milestone yet for Sceye, a US aerospace company based near Albuquerque, New Mexico. — Jeremy Hsu, ArsTechnica, 19 Oct. 2026

Manning reaches the milestone in his 246th regular-season game. — Assistant Sports Editor, Los Angeles Times, 19 Oct. 2026

The stock market has already reached a positive milestone despite growing consternation around the artificial intelligence trade. — Fred Imbert, CNBC, 19 Oct. 2026

The separation placed the sample-return spacecraft on its interplanetary trajectory toward Mars and Phobos, marking a key milestone in the mission. — Aamir Khollam, Interesting Engineering, 19 Oct. 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