The Collaborative International Dictionary of English v.0.48:

oedema \oe*de"ma\, n. [NL., from Gr. ? a swelling, tumor, fr. ?
   to swell.] (Med.)
   A swelling from effusion of watery fluid in the cellular
   tissue beneath the skin or mucous membrance; dropsy of the
   subcutaneous cellular tissue. [Written also edema.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Edema \E*de"ma\, n. [NL.] (Med.)
   Same as [oe]dema. Edematous

WordNet (r) 3.0 (2006):

edema
    n 1: swelling from excessive accumulation of watery fluid in
         cells, tissues, or serous cavities [syn: edema, oedema,
         hydrops, dropsy]

Moby Thesaurus II by Grady Ward, 1.0:

170 Moby Thesaurus words for "edema":
   abscess, access, accession, accretion, accrual, accruement,
   accumulation, addition, advance, aggrandizement, ague,
   amplification, anemia, ankylosis, anoxia, apnea, appreciation,
   ascent, asphyxiation, asthma, ataxia, atrophy, augmentation,
   backache, ballooning, bleeding, blennorhea, bloat, bloatedness,
   bloating, blowing up, boil, boom, boost, broadening, buildup, bump,
   bunion, cachexia, cachexy, carbuncle, chill, chills, colic,
   constipation, convulsion, corn, coughing, crescendo, cyanosis,
   cyst, development, diarrhea, diastole, dilatation, dilation,
   distension, dizziness, dropsy, dysentery, dyspepsia, dyspnea,
   elevation, emaciation, enlargement, expansion, extension, fainting,
   fatigue, fever, fibrillation, flatulence, flatulency, flatus,
   flood, flux, furuncle, gain, gassiness, greatening, growth, gush,
   hemorrhage, high blood pressure, hike, hydrops, hypertension,
   hypotension, icterus, increase, increment, indigestion,
   inflammation, inflation, insomnia, intumescence, itching, jaundice,
   jump, labored breathing, leap, low blood pressure, lumbago, lump,
   marasmus, meteorism, mounting, multiplication, nasal discharge,
   nausea, necrosis, pain, paralysis, pimple, pock, productiveness,
   proliferation, pruritus, puff, puffiness, puffing, pustule, raise,
   rash, rheum, rise, rising, sclerosis, sebaceous cyst, seizure,
   shock, skin eruption, sneezing, snowballing, sore, spasm, spread,
   stretching, surge, swell, swellage, swelling, swollenness, tabes,
   tachycardia, tumefaction, tumescence, tumidity, tumidness, tumor,
   turgescence, turgescency, turgidity, turgidness, tympanism,
   tympany, up, upping, upset stomach, upsurge, upswing, uptrend,
   upturn, vertigo, vomiting, wasting, waxing, wen, widening,
   windiness