This is name given to the power of a legislative branch of government to vote a bill into law even though it has been vetoed by the head of the executive branch.

Explanation:

In some cases, the Congress may override a vetoed bill simply by securing a two-thirds vote in both the House of the Representatives and the  Senate. This process of enacting a vetoed bill is normally called as 'to override a veto.'

To override a veto, both the chambers of the legislature must vote on the bill vetoed by the President.

The Constitution provides Congress with the power to enact and implement bills and laws it finds “mandatory and proper”, therefore, although the President objects or vetoes a certain bill, the Congress can still pass the vetoed bill that it finds necessary through the process of override.