POLYDIPSIA Meaning of POLYDIPSIA in English [ ˌpɒlɪ'dɪpsɪə ]■ noun Medicine abnormally great thirst.OriginC17: from Gk poludipsios 'very thirsty', based on dipsa 'thirst'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004