Plum

plum the fruit of Prunus domestica and other Prunus spp. Other members of the genus include the apricot, peach, sloe, and cherry. The relationship between plums and cherries is particularly close, the distinction being mainly one of size.

The word ‘plum’ has a long history of often ill-defined use. In the Middle Ages it seems to have meant virtually any dried fruit, including raisins, and this usage underlies names such as ‘plum pudding’ and ‘plum cake’. Francesca Greenoak (1983), in her highly readable chapter on the plum family, discusses this point in relation to Christmas (plum) pudding, and suggests that raisins had already supplanted plums before Little Jack Horner (whose rhyme dates from the 16th century) ‘stuck in his thumb’; so that what he pulled out was in fact a raisin.