Nothing but wild seas, but better than the desert sands (5)
I believe the answer is:
oases
'the desert sands' is the definition.
Although both the answer and definition are plural nouns, I don't see how they can define each other.
'nothing but wild seas but better' is the wordplay.
I cannot really see how this works, but
'nothing' could be 'o' (O resembles 0) and 'o' is found within the answer.
an anagram of 'seas' is 'ases' which is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'than' acts as a link.
Can you help me to learn more?
(Other definitions for oases that I've seen before include "These sanctuaries" , "Where there may be dates" , "Fertile desert places" , "Green desert spots" , "Fertile tracts in a desert" .)