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

Griner out Only one point away from a historic milestone, future Hall of Famer Brittney Griner was relegated to the bench with a rib injury on Monday night. —Joseph Dycus, Mercury News, 26 May 2026

Fritz, rusty from a two-month stint out with tendinitis, fell to Nishesh Basavareddy, in an American milestone that came with a double edge. —Matthew Futterman, New York Times, 25 May 2026

The milestone reflects a transition from prototype development to large-scale commercial deployment of humanoid robots. —Jijo Malayil, Interesting Engineering, 24 May 2026

And while all parents are proud that their kids have completed the milestone, graduation can also serve as a reminder that time is moving fast, making the moment extra emotional. —Stephanie Sengwe, PEOPLE, 24 May 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