mon·o·cot·y·le·don / ˌmänəˌkätlˈēdn/ • n. Bot. a flowering plant (class Monocotyledoneae or Liliopsida) with an embryo that bears a single cotyledon (seed leaf). Monocotyledons constitute the smaller of the two great divisions of flowering plants, and typically have elongated stalkless leaves with parallel veins (e.g., grasses, lilies, palms). Compare with dicotyledon.DERIVATIVES: mon·o·cot·y·le·don·ous / -ˈēdn-əs/ adj.

monocotyledon An angiosperm (flowering plant) in which the embryo characteristically has one cotyledon which is usually amplexicaul and, like the later leaves, has parallel nervation. Compare DICOTYLEDON.

monocotyledon Subclass of flowering plants (angiosperms) characterized by one seed leaf (cotyledon) in the seed embryo; the leaves are usually parallel-veined. Examples include lilies, onions, orchids, palms, and grasses. The larger subclass of plants is dicotyledon.