Costermonger, coster, or costard is a street seller of fruit and vegetables, in London and other British towns. Costermongers were ubiquitous in mid-Victorian England, and some are still found in markets. As usual with street-sellers, they would use a loud sing-song cry or chant to attract attention. The costermonger's cart might be stationary at a market stall, or mobile (horse-drawn or wheelbarrow). The term is derived from the words costard (a now extinct medieval variety of large, ribbed apple) and monger (seller). (source)