The Collaborative International Dictionary of English v.0.48:

Edda \Ed"da\, n.; pl. Eddas. [Icel., lit. great-grandmother
   (i. e., of Scandinavian poetry), so called by Bishop
   Brynj['u]lf Sveinsson, who brought it again to light in
   1643.]
   The religious or mythological book of the old Scandinavian
   tribes of German origin, containing two collections of Sagas
   (legends, myths) of the old northern gods and heroes.
   [1913 Webster]

   Note: There are two Eddas. The older, consisting of 39 poems,
         was reduced to writing from oral tradition in Iceland
         between 1050 and 1133. The younger or prose Edda,
         called also the Edda of Snorri, is the work of
         several writers, though usually ascribed to Snorri
         Sturleson, who was born in 1178. Eddaic