noun Botany.
- a dicotyledon.
- 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.