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 company is also targeting several important program milestones that will support the development, production, and commercial rollout of its aircraft. — Bojan Stojkovski, Interesting Engineering, 18 July 2026

Two other workers crossed this milestone, earning more than 100% of their regular salaries in overtime. — Laura Tillman, Hartford Courant, 18 July 2026

Below, find a full list of the potential milestones that The Odyssey’s box office could pass. — Bethy Squires, Vulture, 17 July 2026

Birkenstock is celebrating a major milestone this year as its beloved Boston clog turns 50. — Jaden Thompson, Footwear News, 17 July 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