Grounds that have a hundred and one uses (6)
I believe the answer is:
causes
'grounds that' is the definition.
'causes' can be an answer for 'grounds'. I am not certain of the remainder of the definition.
'a hundred and one uses' is the wordplay.
'a hundred' becomes 'c' (Roman numeral).
'and' says to put letters next to each other.
'one' becomes 'a'.
'c'+'a'+'uses'='CAUSES'
'have' is the link.
Can you help me to learn more?
(Other definitions for causes that I've seen before include "Brings" , "They bring about effects" , "Reasons why things happen" , "They give rise to effects" , "Origins or crusaders" .)