malacosteon
/maləˈkɒstɪɒn/Medicine. Now rare
noun
Originally: any of various conditions causing softening (demineralization) or destruction of bone. Later: specifically osteomalacia.
Origin
Early 19th century; earliest use found in Medical and Physical Journal. From post-classical Latin malacosteon from ancient Greek μαλακο- + ὀστέον bone.