- a plant belonging to the genus Anagallis, of the primrose family, especially A. arvensis (scarlet pimpernel), having scarlet or white flowers that close at the approach of bad weather.
- any of several plants of the primulaceous genus Anagallis, such as the scarlet pimpernel, typically having small star-shaped flowers
- any of several similar and related plants, such as Lysimachia nemorum (yellow pimpernel)
n.c.1400, from Old French pimprenelle, earlier piprenelle (12c.) and directly from Medieval Latin pipinella name of a medicinal plant. This is perhaps from *piperinus “pepper-like” (so called because its fruits resemble peppercorns), a derivative of Latin piper “pepper” (see pepper (n.)); or else it is a corruption of bipinnella, from bipennis “two-winged.” The Scarlet Pimpernel was the code name of the hero in an adventure novel of that name published 1905.