Foster is an English surname with more than one source: most often it is a contracted form of Forester, "forest keeper", but it can also come from the Old English word for a "foster parent" or from the trade of the scissors maker. Songwriter Stephen Foster, author of Oh! Susanna, is its best-known American bearer. Foster hovered between number 937 and 1078 for the past decade and entered the top 1000 in 2025 at number 901.