Merriam-Webster Collegiate Dictionary - edema

 noun  Etymology: New Latin, from Greek oidema swelling, from oidein to swell; akin to Armenian aytnu- swell, Old English ator poison  Date: 15th century  1. an abnormal infiltration and excess accumulation of serous fluid in connective tissue or in a serous cavity — called also dropsy  2.  a. watery swelling of plant organs or parts  b. any of various plant diseases characterized by such swellings  • ~tous adjective