What does balance of powers refer to?

In speaking about the US Federal government, it was created in a fashion to divide the powers of the central government into three branches. By doing so, and delegating a vast amount of power to the states that created it, the nation ensured itself that tyranny could not evolve from the Federal government. Laws must be voted on by a Congress, no law can come into law and be enforced unless the Executive branch has a hand in it. And, despite the actions of the former two branches of government, the Supreme Court can nullify any law or practice by the former two branches that does not meet the standards set by the US Constitution. Also, the members of the US Supreme Court must be nominated by the head of the executive branch, the president, and approved by the Senate. Supreme Court justices can be impeached and removed by the Congress for crimes. This is a two step process. Taken as a whole, the balance of power in the Federal government, is a close as a true balance then can be constructed. And, if it needs to be reconstructed, there is a Constitutional method on how this can be accomplished.