From Longman Dictionary of Contemporary Englishmilepostmile‧post /ˈmaɪlpəʊst $ -poʊst/ noun [countable] American English 1 TTDISTANCEa post next to a road or railway that shows the distance in miles to the next town2 a milestone(1)
Examples from the Corpus
milepost• Far from being a defeat, Reykjavik was a milepost, a turning point in disarmament negotiations.• Victoria and I have undoubtedly passed that milepost. 