noun (n)

• submerged aquatic plant having narrow leaves and small flowers; of fresh or brackish water(noun.plant)

  Synonym:
  water nymph
  

  source: wordnet30
• (Greek mythology) a nymph of lakes and springs and rivers and fountains(noun.person)

  source: wordnet30
• A water nymph; one of the lower female divinities, fabled to preside over some body of fresh water, as a lake, river, brook, or fountain.(noun)

  source: webster1913