c.1400, from Gk. oidema (gen. oidematos) "a swelling tumor," from oidein "to swell," from oidos "tumor, swelling," from PIE *oid- "to swell;" cf. L. aemidus "swelling," O.N. eista "testicle," O.E. attor "poison" (that which makes the body swell), and the first element in Oedipus.
