Your twenty-first birthday is a milestone in your life.
- An example of a milestone is when the court makes a sweeping change in the civil rights law.
- An example of milestone is a person's 16th birthday.
- a stone or pillar set up to show the distance in miles to or from a specified place
- a significant or important event in history, in the career of a person, etc.
- A stone marker set up on a roadside to indicate the distance in miles from a given point.
- An important event, as in a child's development, the history of a nation, or the advancement of knowledge in a field; a turning point.
(third-person singular simple present milestones, present participle milestoning, simple past and past participle milestoned)
- To place milestones along (a road, etc.).
- To plan out a project as a series of major steps.