'hypochondriac' originates from Greek, specifically the word 'hypochondriakos' (from 'hypochondrion'), where 'hypo-' meant 'under' and 'chondros' meant 'cartilage' (the cartilage of the ribs).

'hypochondriac' passed into Late Latin as 'hypochondriacus' and then into English (via medical Latin and French influence) as 'hypochondriac'; the term originally referred to the region below the ribs and later to disorders thought to originate there.

Initially, it meant 'relating to the area beneath the ribs'; over time it came to mean 'a person excessively anxious about their health' (the medical/anxiety sense).