Why is the ninth month called September?
mid-15c., "bedroom," from Latin cubiculum "bedroom," from cubare "to lie down," originally "bend oneself," from PIE root *keu(b)- "to bend, turn." With Latin -clom, suffix denoting place. Obsolete from 16c. but revived 19c. for "dormitory sleeping compartment," sense of "any partitioned space" (such as a library carrel or, later, office work station) is first recorded 1926.