5 Mils postage stamp from the British Mandate of Palestine. 
Denomination: The stamp has a value of "5 Mils," indicated both numerically and in text ("FIVE MILS" or "FIVE ADIEMES" as seen in the image description).
Language: The stamp features text in three languages: English ("POSTAGE," "PALESTINE," "PAID"), Arabic (فلسطين, which means Palestine), and Hebrew (פלשתינה א"י, an abbreviation for Eretz Yisrael, meaning Land of Israel).
Historical Context: These stamps were issued during the British Mandate period in Palestine, which lasted from 1920 to 1948.
Purpose: As a postage stamp, its primary function was to indicate that postage had been paid for mail sent from within or through Palestine during that era.