Material that's used in construction (8)
I believe the answer is:
concrete
'material' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for concrete that I've seen before include "setter" , "Strong, hard, building material" , "Specific; definite" , "Definite; building material" , "It's composed of sand, cement and water" .)