It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Let the people of the desert (the Bedouins) never prevail over you in the matter of the name of your prayer. Allah Almighty has named it 'Isha', while they call it 'Atamah'."
Hadith Referenceالمعجم الأوسط / باب الميم / 7391
Hadith Takhrij«أخرجه ابن ماجه فى «سننه» برقم: 705، وأحمد فى «مسنده» برقم: 9731، 9790، والبزار فى «مسنده» برقم: 8487»