mile·​stone | \ˈmī(-ə)l-ˌstōn \

Definition of milestone 

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

Illustration of milestone

milestone 1

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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

Women also hit a series of significant milestones, including the first Native American women elected to Congress, the first Muslim women sent to represent their states in the House, and the youngest women to serve as lawmakers. Recode Staff, Recode, "Recode Daily: Trump’s first post-midterms move: Dump Attorney General Jeff Sessions," 8 Nov. 2018 The former actress has already reached a bunch of royal family milestones, from her first solo event with Queen Elizabeth, to her first Wimbledon in the royal box. Kayleigh Roberts, Marie Claire, "Meghan Markle and Kate Middleton's First Solo Speeches as Royals, Compared," 22 Sep. 2018 The approval of a generic version of this product marks something of a milestone for FDA Commissioner Scott Gottlieb. Thomas M. Burton, WSJ, "FDA Approves Teva’s Generic Version of EpiPen Injector," 16 Aug. 2018 Today, Princess Anne, the Princess Royal, turns 68, and in honor of the milestone, her royal relatives are sending her birthday wishes on social media. Caroline Hallemann, Town & Country, "How the Royal Family Is Celebrating Princess Anne's Birthday Today," 15 Aug. 2018 One thing that remains unclear is whether Tesla passed a different kind of milestone at the end of this past quarter. Sean O'kane, The Verge, "Tesla lost its chief engineer just before hitting Elon Musk’s Model 3 goal," 2 July 2018 Americans witnessed a succession of political milestones from the appointment of the first female Secretary of State to the first female Attorney General and the first black woman in the Senate. Rhaina Cohen, The New Republic, "What the 1990s Got Wrong," 29 June 2018 The department is working to attract female and minority applicants, said Tavares, who has reached a number of milestones in Bristol. Don Stacom, Courant Community, "Bristol Seeks Police Applicants," 27 June 2018 One of the biggest milestones of Sofi Tukker was their first studio album release, Treehouse, in April. Billboard Radio China, Billboard, "Sofi Tukker Tell Story of 'Best Friend' Song, 'Treehouse' Debut Album," 14 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'milestone.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of milestone

1662, in the meaning defined at sense 1

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Statistics for milestone

Last Updated

28 Nov 2018

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Time Traveler for milestone

The first known use of milestone was in 1662

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English Language Learners Definition of milestone

: a stone by the side of a road that shows the distance in miles to a specified place

: an important point in the progress or development of something : a very important event or advance


mile·​stone | \ˈmīl-ˌstōn \

Kids Definition of milestone

1 : a stone by the side of a road showing the distance in miles to a given place

2 : an important point in progress or development His discovery was a major milestone in scientific research.

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to enclose within walls

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