Why is the ninth month called September?
c.1300, "wheeled vehicle," from Anglo-French carre, Old North French carre, from Vulgar Latin *carra, related to Latin carrum, carrus (plural carra), originally "two-wheeled Celtic war chariot," from Gaulish karros, a Celtic word (cf. Old Irish and Welsh carr "cart, wagon," Breton karr "chariot"), from PIE *krsos, from root *kers- "to run" (see current (adj.)).
"From 16th to 19th c. chiefly poetic, with associations of dignity, solemnity, or splendour ..." [OED]. Used in U.S. of railway carriages by 1826; extension to "automobile" is by 1896. Car bomb first 1972, in reference to Northern Ireland. The Latin word also is the source of Italian and Spanish carro, French char.