What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
1The respiratory system of an animal, or part of this.
2Equipment that enables breathing in airless or toxic environments, as in diving, mining, firefighting, etc.
3Equipment that maintains respiration in cases of respiratory damage or failure.
Mid 19th century; earliest use found in Philosophical Transactions of the Royal Society of London.