What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
1Chiefly Architecture and Civil Engineering a supporting, protecting, or retaining wall built at the front or top of a structure, area, etc.
2Physical Geography and Mountaineering a steep rock slope at the head of a valley; especially a rock face or cliff at the back of a corrie.
Mid 17th century.