What is the term for the power of a president to reject a bill passed by the legislature?

Veto

The word 'veto' comes from the Latin for 'I forbid,' a power originally held by the tribunes of ancient Rome to protect the common people from the Senate. In the U.S. system, a presidential veto is a key check and balance that can only be overridden by a two-thirds majority vote in both the House and Senate. This high threshold ensures that laws generally require broad consensus to pass over executive opposition.