Musnad Ahmad 30:3472

Yazid narrated to us, Hisham ibn Hassan informed us, from Muhammad ibn Sirin, from Abu Hurairah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Let not one of you say: 'My slave' (abdi), 'my slave-girl' (amati). But let him say: 'My young man' (fatay) and 'my young woman' (fatati)."