Webster's Revised Unabridged Dictionary · 1913

Monocotyledon

Monocotyledon , noun

[Mono- + cotyledon: compare French monocotylédone.]

(Botany) A plant with only one cotyledon, or seed lobe; a member of the Monocotyledonae.

The plural, monocotyledons, is used as the name of a large class of plants (the Monocotyledones, or Monocotyledonae), and is generally understood to be equivalent to the term endogens.