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 first tangible milestone arrived this summer with the opening of a new Nobu restaurant in the Eastown District of New Cairo, offering diners a teaser of the brand ahead of the future Nobu Hotel (set to open next year). — Nick Scott, Robb Report, 22 Aug. 2026

Whenever the household experienced a milestone — a reunion, for example — Dick and Bunny would put out banners to mark the occasion. — David Caraccio, Sacbee.com, 22 Aug. 2026

Just last week, the singer was tied with Maroon 5, as both acts had collected a milestone 15 leaders. — Hugh McIntyre, Forbes.com, 22 Aug. 2026

The Guardians took the lead when Adell followed Ramirez’s milestone single with a three-run homer, his 20th of the season. — ABC News, 22 Aug. 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