Olive and Laurel take data from Great Danes (6)
I believe the answer is:
greens
'take data from great danes' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'olive and laurel' is the wordplay.
'olive' becomes 'green' (green olive is a kind of olive).
'and' is a charade indicator (letters next to each other).
'laurel' becomes 's' (I can't justify this - if you can you should give a lot more credence to this answer).
'green'+'s'='GREENS'
Can you help me to learn more?
(Other definitions for greens that I've seen before include "Nature lovers" , "Veg" , "Leaves" , "those joining in the party" , "party politicians" .)