Early, possibly heartless, seat of learning (4)
I believe the answer is:
yale
This might be a double definition.
'early possibly heartless seat' is the first definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'learning' is the second definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'of' is the link.
Can you help me to learn more?
(Other definitions for yale that I've seen before include "security device" , "New Haven university" , "US university; lock" , "Educational institution" , "Thief might gain entrance after picking this" .)