Real Dictionary

hawthorn
variable noun: A hawthorn is a small tree which has sharp thorns and produces white or pink flowers.

hawthorn in American English
any of a group of thorny shrubs and small trees (genus Crataegus) of the rose family, with white, pink, or red flowers and usually red fruits (haws) resembling miniature cherries
noun: any of numerous plants belonging to the genus Crataegus, of the rose family, typically a small tree with stiff thorns, certain North American species of which have white or pink blossoms and bright-colored fruits and are cultivated in hedges

hawthorn in British English
noun: any of various thorny trees or shrubs of the N temperate rosaceous genus Crataegus, esp C. oxyacantha, having white or pink flowers and reddish fruits (haws)