Old poems from the east, almost all augmented (4)
I believe the answer is:
edda
'old' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for edda that I've seen before include "Ancient books" , "Norse story" , "One of the two old Icelandic poetic books" , "Old Scandinavian book of poetry, etc" , "Scandinavian books of myths" .)