Original sentence: While there are various older or different definitions of the term "Palestinian" (discussed in a section of Definitions of Palestine), the overwhelming majority of uses of the term today are in reference to the people, mainly Arabs, whose ancestors inhabited Palestine before 1918
Edited sentence: Their ancestors inhabited Palestine before 1918.While there are various older or different definitions of the term "Palestinian" (discussed in a section of Definitions of Palestine), the overwhelming majority of uses of the term today are in reference to these people