1/10 The Arabic word for monotheism, tawḥīd, does not appear in the Qur’an.
But the Qur’an has other ways of referring to monotheism.
One is to couple the term dīn, which means “worship,” with words from the root kh-l-ṣ (e.g., mukhliṣ), which conveys exclusivity/purity.