UNHCR:
The primary and universal definition of a refugee that applies to States is contained in Article 1(A)(2) of the 1951 Convention, as amended by its 1967 Protocol, defining a refugee as someone who:
"owing to well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his nationality and is unable or, owing to such fear, is unwilling to avail himself of the protection of that country; or who, not having a nationality and being outside the country of his former habitual residence, is unable or, owing to such fear, is unwilling to return to it.
UNRWA:
Palestine refugees are defined as “persons [and descendants of persons] whose normal place of residence was Palestine during the period 1 June 1946 to 15 May 1948, and who lost both home and means of livelihood as a result of the 1948 conflict.”