Understand concrete is European (7)
I believe the answer is:
realise
'understand' is the definition.
('understand'->'realize' is in my internal thesaurus and 'ize'->'ise')
'concrete is european' is the wordplay.
'concrete' becomes 'real' ('real' can be similar in meaning to 'concrete').
'european' becomes 'e' (abbreviation e.g. EU).
'real'+'is'+'e'='REALISE'
(Other definitions for realise that I've seen before include "produce" , "Come to know" , "Become fully aware of" , "Be fully aware of or convert plan into fact" , "Apprehend; see lair (anag.)" .)