Coster \c(o)-ster, cos-ter\ as a boy's name is of Old English origin, and the meaning of Coster is "peddler". From "costermonger", meaning "seller of costards". A costard was originally a native English apple, a large medieval variety that no longer exists.

Baby names that sound like Coster are Caster, Castor and Kester. Other similar baby names are Colter and Foster.