What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
Any of various aquatic plants with finely divided submerged leaves, especially water violet (genus Hottonia) and water milfoil (or parrot's feather) (genus Myriophyllum).
Early 19th century; earliest use found in Thomas Nuttall (1786–1859), botanist.