pennyroyal

noun

1. an aromatic Old World plant, Mentha pulegium, of the mint family, having clusters of small purple flowers and yielding a pungent essential oil used medicinally and as an insect repellent.
2. Also called mock pennyroyal. a similar, related plant, Hedeoma pulegioides, of eastern North America, having bluish flowers growing from the leaf axils.
3. any of several other aromatic plants of the mint family.

noun

1. a Eurasian plant, Mentha pulegium, with hairy leaves and small mauve flowers, that yields an aromatic oil used in medicine: family Lamiaceae (labiates)
2. Also called: mock pennyroyal a similar and related plant, Hedeoma pulegioides, of E North America

n.herb, 1520s, alteration by folk etymology of Anglo-French puliol real; for second element see royal; first element ultimately from Latin puleium “thyme,” of unknown origin.