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

This year marks two important milestones for Carolina Herrera — the American fashion brand’s 45th anniversary and the 10th anniversary of its Good Girl fragrance. — Emily Mercer, Footwear News, 14 Sep. 2026

Tech stocks slid worldwide Monday after another jump in oil prices briefly pushed the 10-year Treasury yield to 5%, marking the bond market’s latest pressure-raising milestone. — Stan Choe, Los Angeles Times, 14 Sep. 2026

Europe’s space ambitions reached a milestone earlier this month when German startup Isar Aerospace became the first commercial European company to put satellites into orbit. — Elsa Ohlen, CNBC, 14 Sep. 2026

To celebrate this milestone occasion, Disney and Lucasfilm are bringing the original Star Wars theatrical release to IMAX screens for the first time. — Jeff Spry, Space.com, 14 Sep. 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