Milepost (noun)

1. A marker, typically made of stone or metal, placed at intervals along a road, showing the distance travelled.
2. A significant point or stage in a journey, career, or process.

Origin:

The term 'milepost' originated from late 17th century, from the idea of a post marking miles along a road. the term was first used to refer to markers or milestones along a highway.

Examples:

1. The mileposts along the highway indicated how far we still had to go.
2. Getting this job was a milepost in my career and I was very proud of it.
3. The milepost showed that the next town was only 10 miles away.
4. Reaching the summit of the mountain was a milepost in the team's journey.
5. This project is a milepost in the company's history and will be remembered for years to come.