Obviously a Dummycrap started that term. Leftards are good at branding from “global warming”, “Net Neutrality”, “social justice” etc but empty at their meaning.
The lands were won in the 67 war and by law, Israel has to provide a govt for the Palestinians, which is a military govt law by the IDF that must be kept separate from Israeli law because if you let the Palestenians use Israeli law then they can claim to be Israelis. So the IDF is a military occupation of Palestine.
For a better understanding look at the Israeli documentariy "The Law in these Parts", which is based on interviews with military commanders and military judges who set up the occupation in earlier times. Also in that documentary they explain the law that was used to legally establish settlements