From French hypocondriaque, from Ancient Greek ὑποχονδριακός (hupokhondriakós, “of the region between the ribs and navel”), from ὑποχόνδριος (hupokhóndrios, “the space between the ribs and the navel”), from ὑπό (hupó, “below”) + χόνδρος (khóndros, “cartilage”). See also hypochondrium, hypochondria, and Wikipedia at hypochondriasis § Etymology.