Noun
a group of chiefly woody plants considered among the most primitive of angiosperms; perianth poorly developed or lacking; flowers often unisexual and often in catkins and often wind pollinated; contains 23 families including the Betulaceae and Fagaceae (includes the Amentiferae); sometimes classified as a superorder
Source: WordNetApiales, Cornales, Proteales and Santalales, and parts of Rafflesiales (sensu Cronquist) are excluded from the second, and many groups from Cronquist's Hamamelidae and Dillenidae are included. Source: Internet