It centres around cross (9)
I believe the answer is:
intersect
'cross' is the definition.
(I know that cross can be written as intersect)
'it centres around' is the wordplay.
'around' indicates anagramming the letters.
'it'+'centres'='itcentres'
'itcentres' anagrammed gives 'INTERSECT'.
(Other definitions for intersect that I've seen before include "Cut across" , "Criss-cross" , "making one cross" , "Divide into parts" , "Meet at a point" .)