Apple (here) makes an excellent reply to someone making the familiar claim that "before 1948 there were no Palestinians:
...they did call themselves "Palestinians" before 1948 - and so did the Jews. It was the word - used by everyone - who lived in Palestine. You can see it used in the New York Times, for instance, as early as 1894
I checked the Times archives and found apple was right. For instance:
From April 1898: The Jewish Passover, or the Feast of Unleavened Bread, will be ushered in at sundown to-day. It will be universally observed by orthodox Jews for eight days and by their reformed and Palestinian brethren for seven days.
From August 1921: A deputation of Syrian and Palestinian notabilities, headed by Prince Michel Lotfallah, today submitted to the League of Nations an expression of the desire of the Syrian and Palestinian populations for complete independence of any outside power. They object to France having a mandate over Syria and to Palestine becoming a national home for the Jews
From May 1938: Hassan a Rifaat Pasha, Under-Secretary of the Interior, will summon tomorrow Palestinian Arab leaders now residing here as political refugees and will warn them that unless they refrain from political activities here, particularly concerning Palestine, the Egyptian Government will be forced to withdraw its hospitality and to deport them.
There are many, many more of these, dating to the late 19th century (I'm only able to see the first paragraph of the search results)