Monocot. Definition. noun, plural: monocotyledons. A group of flowering plants belonging to the class Liliopsida (or Monocotyledonae) of Angiospermae (angiosperms), characterized by having only one cotyledon in the seed and an endogenous manner of growth.Supplement.Examples of monocotyledonous plants are the palms, grasses, orchids, and lilies.The angiosperms (the flowering plants) can either be a monocotyledon (or monocot) or a dicotyledon (or dicot) according to the number of cotyledons in their seeds.xamples of monocotyledonous plants are the palms, grasses, orchids, and lilies. The angiosperms (the flowering plants) can either be a monocotyledon (or monocot) or a dicotyledon (or dicot) according to the number of cotyledons in their seeds.