Assumption
Assumption: Taking on another person's obligation or a known risk. For example, a home buyer who assumes a mortgage takes over the seller's loan, often with the lender's consent. Tort law also has a defense called assumption of risk, which applies when an injured person knowingly accepted a danger. Likewise, a party may assume a duty under a contract, and a debtor in bankruptcy may assume or reject certain contracts under 11 U.S.C. § 365.

What assumption means
Put simply, assumption is part of the working vocabulary of a civil case. The short definition above covers the usual meaning. Still, a specific rule, statute or contract can give it a narrower meaning. For that reason, check how it is used in your own documents.
Where assumption comes up
The term is used across many kinds of cases. For example, you may see it in pleadings, motions and court orders. To see it in context, browse the motions and procedures library or the Learn the Law topics.
Read the source: Presumption.
How to research the term
To research assumption, begin with the rule, statute or contract where the word is used. Each one can give it a slightly different meaning. Then compare that text with how courts in your area have applied it. Also check the local rules of your court, since they can add requirements. If your case is in state court, the state rules control. So start with our state procedures guide to find them. In the end, always confirm that the source you rely on is current.
You can read the current federal court rules online for free.
Related legal terms
- Assignee: the party who receives rights in an assignment.
- Assignment: a transfer of rights, such as the right to receive payment under a contract or note, from one party (the assignor) to another (the assignee).
- Assignment of mortgage: a recorded document transferring the mortgagee's interest in a mortgage or deed of trust to another party.
- Assignor: the party who transfers rights in an assignment.
Why precise terms matter
Courts read legal terms closely. As a result, knowing the exact meaning of a word helps you follow orders, rules and filings. Each glossary entry on Lawtopolis is short on purpose and links to the pages where the term is used.
Sources
Sources last reviewed: 2026-10-24
Lawtopolis provides legal information and education, not legal advice. Using this site does not create an attorney-client relationship. Laws and court rules vary by jurisdiction and change over time; verify every authority against the official source and consult a licensed attorney in your jurisdiction about your situation.
