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

At the present time, with reusable rockets that require little maintenance (other that refueling) between launches, launch costs are finally coming down to approach the $1000 per kg milestone. —Big Think, 24 Feb. 2026

That's a monumental milestone for this church, which saw construction originally begin all the way back in 1882. —New Atlas, 23 Feb. 2026

The gathering was held to commemorate construction and campaign milestones. —Lou Ponsi, Oc Register, 23 Feb. 2026

While the slideshow was all about the milestone, Michael (and his striking genes) took the spotlight. —Christina Perrier, InStyle, 23 Feb. 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