The phrase by operation of law is a legal term that indicates that a right or liability has been created for a party, irrespective of the intent of that party, because it is dictated by existing legal principles. For example, if a person dies without a will, his heirs are determined by operation of law. Similarly, if a person marries or bears a child after their will has been executed, the law writes this pretermitted spouse or pretermitted heir into the will. Adverse possession, in which title to land passes because non-owners have occupied it for a certain period of time, is another important right that vests by operation of law. This is a list of legal terms, often from Latin: A mensa et thoro A mensa et thoro, from bed and board. ... In the law, a will or testament is a documentary instrument by which a person (the testator) regulates the rights of others over the testators property or family after their death. ... For other uses, see inheritance (disambiguation). ... In real estate law, adverse possession is a means of acquiring title to anothers real property without compensation. ...

Generally, rights or liabilities created by operation of law are created because a contingency occurs for which a party's has failed to plan (e.g. failure to write a will); or because a specific condition exists for a set period of time (e.g. adverse possession of property or creation of an easement; failure of a court to rule on a motion within a certain period automatically defeating the motion; failure of a party to act on a filed complaint within a certain time causing dismissal of the case); or because an existing legal relationship is invalidated, but the parties to that relationship still require a mechanism to distribute their rights (e.g. under the Uniform Commercial Code, where a contract for which both parties have performed partially is voided, the court will create a new contract based on the performance that has actually been rendered, and containing reasonable terms to accommodate the expectations of the parties). An easement is the right of use over the real property of another. ... The Uniform Commercial Code is one of the Uniform Acts that attempts to harmonise the law of the fifty U.S. states in the United States of America. ...