IPA: /ˈoʊ.nə.nɪ.zəm/
KK: /o'nænɪzəm/
The act of stimulating one's own genitals for sexual pleasure, often leading to orgasm.
Many people consider onanism a natural part of human sexuality.
Onanism originates from the name 'Onan' (from Hebrew 'עוֹנָן', meaning to be strong or vigorous), a biblical figure mentioned in the Book of Genesis who practiced coitus interruptus. The term has come to refer to masturbation, drawing from the story of Onan's actions.
Think of the biblical figure Onan, who is associated with the act of interrupting a natural process, which helps you remember that onanism refers to masturbation.