/ ˌəʊvəˈtɜːn; NAmE ˌoʊvərˈtɜːrn/ verb
1.
if sth overturns , or if sb overturns it, it turns upside down or on its side :
[ v ]
The car skidded and overturned.
[ vn ]
He stood up quickly, overturning his chair.
2.
[ vn ] to officially decide that a legal decision etc. is not correct, and to make it no longer valid :
to overturn a decision / conviction / verdict
His sentence was overturned by the appeal court.