IPA: /ˌmɒnəʊθɪˈɪstɪk/
KK: /mɑnəˈθiːɪstɪk/
Relating to the belief in only one god or deity, often associated with certain religions.
Many major religions, such as Christianity and Islam, are monotheistic.
Monotheistic → It is formed from "mono-" (from Greek "monos", meaning single or alone) and "theos" (meaning god). The word "monotheistic" refers to the belief in a single god.
Think of 'mono-' meaning 'single' and 'theos' meaning 'god' — this helps you remember that monotheistic refers to the belief in one god.