- any angiospermous plant of the class (or subclass) Dicotyledoneae, producing seeds with two cotyledons and having an exogenous manner of growth.
- any flowering plant of the class Dicotyledonae, normally having two embryonic seed leaves and leaves with netlike veins. The group includes many herbaceous plants and most families of trees and shrubs
- primitive dicotyledon . any living relative of early angiosperms that branched off before the evolution of monocotyledons and eudicotyledons. The group comprises about 5 per cent of the world’s plants
- An angiosperm that is not a monocotyledon, having two cotyledons in the seed. The term dicotyledon serves as a convenient label for the eudicotyledons, the magnoliids, and a varied group of other angiosperms, but it does not correspond to a single taxonomic group. Compare monocotyledon. See more at eudicotyledon leaf magnoliid.