'megalophthalmos' originates from Greek via New Latin/medical usage, specifically from the Greek elements 'megal(o)-' and 'ophthalmos', where 'megas' meant 'large' and 'ophthalmos' meant 'eye'.

'megalophthalmos' entered medical Latin/terminology from Greek ('megalophthalmos') and was adopted into modern medical English with essentially the same form and meaning.

Initially formed to mean 'large eye' in Greek-derived medical terminology; over time it has come to denote the pathological condition of an abnormally enlarged eyeball (often congenital).