Noun | 1. | Najas - sole genus of the family Naiadaceae liliopsid genus, monocot genus - genus of flowering plants having a single cotyledon (embryonic leaf) in the seed family Naiadaceae, family Najadaceae, naiad family, Naiadaceae, Najadaceae - monotypic family of aquatic plants having narrow leaves and small flowers naiad, water nymph - submerged aquatic plant having narrow leaves and small flowers; of fresh or brackish water |