milestone
//ˈmaɪl.stəʊn//
Noun
milestoneSingular
milestonesPlural
1
A stone marker set up on a road to indicate the distance in miles to a particular place.
The old milestone by the road showed that London was 50 miles away.
2
A significant event, achievement, or stage in the development of something.
Graduating from university was a major milestone in her life.