1 [intransitive and transitive]
if you overturn something, or if it overturns, it turns upside down or falls over on its side:
Leslie jumped to her feet, overturning her chair.
His car overturned, trapping him inside.
to change a decision or result so that it becomes the opposite of what it was before:
His conviction was overturned by the Court of Appeal.
to suddenly remove a government from power, especially by using violence [= overthrow]