mile + stone.
milestone (plural milestones)
- A stone milepost (or by extension in other materials), one of a series of numbered markers placed along a road at regular intervals, typically at the side of the road or in a median.
- An important event in a person's life or career, in the history of a nation, in the life of some project, etc.
2012 March-April, Terrence J. Sejnowski, “Well-connected Brains”, American Scientist, volume 100, number 2, page 171:
- Creating a complete map of the human connectome would therefore be a monumental milestone but not the end of the journey to understanding how our brains work.
one of a series of numbered markers placed along a road at regular intervals
- Japanese: マイルストーン (ja) (mairusutōn), キロポスト (kiroposuto), 里程標 (りていひょう, riteihyō)
- Norman: pièrre dé mille f
- Macedonian: милјоказ m (míljokaz)
- Bokmål: milestein m, milepæl m, milepel m, milestolpe m
- Nynorsk: milestein m, milepåle m, milestolpe
- Portuguese: marco miliário m, marco miliar
- Russian: мильный камень m (míl'nyj kámen'), километровый столб m (kilometróvyj stolb)
- Scottish Gaelic: clach-mhìle f
- Serbo-Croatian: miljokaz
- Slovak: míľnik m
- Spanish: hito (es) m, mojón (es) m
- Swedish: milsten c
- Volapük: liölaston
milestone (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.