What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
The monovalent radical —OC₂₀H₃₉, derived from phytol by the loss of a hydrogen atom, and present as a constituent in various biologically important molecules including chlorophyll and vitamins E and K.
Early 20th century; earliest use found in Journal of the Chemical Society. From phyt- + -yl.