Other forms: mileposts
A milepost is a post by a road showing the distance. Pass the milepost.
They were put up along turnpike roads so that coaches could be charged by distance. A milepost also means a stage in a long process, which is the figurative use.
1nounmilepostA post by a road showing the distance.
“The old milepost still gave the distance to a town that had changed its name.”
milepost is a marker.
From mile + post.
Etymology from Wiktionary, CC BY-SA