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

• 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

Both benchmark gauges hit several record closes this week, with the S & P 500 reaching the milestone on Tuesday, Wednesday, and Thursday. —Morgan Chittum, CNBC, 16 Aug. 2025

Swift even shared a sweet TikTok of Lively on set to celebrate the milestone. —Kelsie Gibson, People.com, 15 Aug. 2025

At the box office, Superman crossed the $500 million milestone, with $333 million in domestic and $249 million in international sales contributing to the half-billion total, according to Box Office Mojo. —Monica Mercuri, Forbes.com, 15 Aug. 2025

So the purchase consisted of $443 million for the unowned portion and up to $221 million upon reaching certain regulatory milestones. —Hang Nguyen, San Diego Union-Tribune, 15 Aug. 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