Monument of wisdom? (6)
I believe the answer is:
pillar
This could be a double definition.
'monument' is the first definition.
(thesaurus)
'wisdom?' is the second definition.
The definition and answer can be both related to thinking as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'of' acts as a link.
Can you help me to learn more?
(Other definitions for pillar that I've seen before include "Column, support" , "Tall support" , "Tall vertical structure, of stone say" , "Vertical stone support" , "Support structure" .)