Legal Definition of Annulment: The act of canceling something; making it void. An annulment of marriage is a legal decision that the marriage never existed. (An annulment is not a divorce.) | Learn the basics of annulment and why it’s important in legal, financial, and religious aspects. Discover how annulment differs from divorce and its impact on property division, child custody, and more. Understand why individuals may prefer annulment for legal clarity, religious beliefs, social stigma, and financial implications. Start making informed decisions with this comprehensive guide