The Spanish word 'hidropesía' (meaning dropsy, an old medical term for fluid retention/swelling) comes from Medieval Latin 'hydropisia', which developed from Latin 'hydropisis'. These Latin terms trace back to the Ancient Greek word 'ὕδρωψ' (hydrops), meaning dropsy. The Greek word itself is a compound of two elements: 'ὕδωρ' (hydor) meaning 'water' and 'ωπος' (opos) meaning 'face or appearance' - literally describing the appearance or manifestation of water in the body.

Several common Spanish words share the 'hidr-' root relating to water, such as 'hidrato' (hydrate), 'hidráulico' (hydraulic), and 'deshidratar' (dehydrate). All these words preserve the connection to the original Greek word for water, 'hydor'.

English speakers might recognize this etymology in words like 'hydration', 'hydraulic', and 'hydrant', all containing the same Greek root 'hydor' (water). The medical condition that 'hidropesía' refers to is now more commonly known in English as 'edema', but the old term 'dropsy' was actually a shortened form of 'hydropsy', showing its connection to the same Greek root.