Sahih Muslim
644.01

Abdullah b. 'Umar reported:I heard the Messenger of Allah (ﷺ) as saying: Let the bedouin not gain upper hand over you in regard to the name of your prayer. See I (The night prayer should be called) 'Isya' (and the bedouins call it Atama (because) they milk their camels late

644.02

Ibn 'Umar said:The Messenger of Allah (ﷺ) said: Let the bedouin not gain upper band over you In regard to the name of your prayer, i. e. night prayer, for it is mentioned 'Isya' in the Book of Allah (i. e. the Qur'an). (The bedouin call it 'Atama because) they make delay in milling their she-camels