A court ruling that says a marriage was never legally valid.

"Court ruling" matters because a couple is not legally unmarried just because they split up or agree the marriage should not count. A judge has to sign off. "Never legally valid" is the key difference from a divorce: divorce ends a valid marriage, while an annulment treats the marriage as invalid from the start. Courts usually require a specific reason, such as fraud, force, lack of mental capacity, being underage without proper consent, bigamy, close blood relation, or physical incapacity that existed at the time of marriage.

In Illinois, people still say annulment, but the formal term under the Illinois Marriage and Dissolution of Marriage Act is a declaration of invalidity of marriage. The deadlines depend on the reason. For example, some claims must be filed within 90 days after learning the problem, while others can be brought before the underage spouse turns 18 or within set periods after cohabitation stops. Waiting too long can kill the case.

Practically, that ruling can change property rights, spousal support, inheritance, health insurance coverage, and who counts as a legal spouse in a case. In an injury claim, that can affect a loss of consortium claim, access to settlement funds, or whether someone can act as next of kin in a wrongful death case. When marriage validity is shaky, get the paperwork checked early.