What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
A transient membrane covering the crown of a newly erupted tooth; the primary enamel cuticle.
Mid 19th century; earliest use found in Quarterly Journal of Microscopical Science. From the genitive of the name of Alexander Nasmyth (d. 1848), British dentist, who described the membrane in 1839 + membrane.