Palestine is a term that refers to the land of Israel. It was originally used by Herodotus, a Greek historian, who named it after a nation – the Phillistines – who once lived on the southwest of the country and were dispersed. When the Jews revolted against the Roman Empire in the Bar Cochba Revolt (132-135 CE) and lost, the Roman Emperor Hadrian gave the land of Israel the name Syrio-Palestina, so as to erase any Jewish connection to the land. After that, Palestine became the common term used by Christians and Westerners for the land of Israel.
It is important to mention that no state of Palestine ever actually existed, nor did a people identifying as Palestinians exist prior to the early 20th century. The land of Israel was ruled by many empires, and it was usually divided into various administrative districts. The local populace, which often shifted, identified itself through religion (Christian, Muslim, Jewish) or ethnicity (Arab, Greek etc).