Buttermilk is a compound of butter + milk, denoting the liquid remaining after churning butter from milk. Butter is from Old English butere, from Latin butyrum; milk from Old English meolc. The historical trail runs through butere in Old English and meolc in Old English. Morphologically, buttermilk is transparent: it is a compound of butter + milk, denoting the liquid remaining after churning butter from milk. Used as a noun, buttermilk now means "the tangy liquid left after churning butter, used in baking", so the present definition can be read against the older forms and meanings. The same lexical family is also visible in related forms such as butter and milk. The result is a borrowed or transmitted form whose modern spelling carries a compact record of its route into English.