LORDOSIS

noun (plural lordoses) Etymology: New Latin, from Greek lordōsis, from lordos curving forward; akin to Old English belyrtan to deceive Date: 1704 abnormally increased inward curvature of the lower region of the spine resulting in a concave back as viewed from the side, a mating posture of some sexually receptive female mammals (as rats) in which the head and rump are raised and the back is arched downward, lordotic adjective