kul primarily denotes a male slave and stands in contrast to küŋ ‘female slave’; the Old Uyghur corpus also has the pair kul küŋ ‘male slave and female slave’. The inscriptional phrase beglik urı oğlın kul kıltı ‘they made their sons, who were fit to be begs, into slaves’ confirms the concrete meaning. The word could also denote a servant, subordinate or dependent; in Islamic usage it developed the meaning ‘servant/slave of God’ and consequently could also be used more generally for a human being. In some early social contexts it may therefore denote a vassal or dependent rather than necessarily a slave in the narrower legal sense.