From Arabic فَتْح (fatḥ), a reverse acronym (meaning literally "conquest, victory or an outcome") for حَرَكَة اَلتَّحْرِير اَلْوَطَنِيّ اَلْفِلَسْطِينِيّ (ḥaraka(t) at-taḥrīr al-waṭaniyy al-filasṭīniyy, “Palestinian National Liberation Movement”).

Etymology: Wiktionary (CC-BY-SA)