North Jay Construction Lawyer, Maine

Principles of international law so fundamental that no nation may ignore them or attempt to contract out of them through treaties. For example, genocide and participating in a slave trade are thought to be jus cogens.

The terms of your contract with an airline after you buy a ticket. Conditions of carriage cover everything from baggage limitations to the amount of compensation you can recover if you're injured on the flight. These provisions often vary from airline to airline. A few, but by no means most, conditions of carriage appear in the fine print on the back of your ticket. To find out about the rest, you can ask the airline for a copy; it is legally obligated to provide one. The conditions of carriage contain a lot of fine print detail and will not make for exciting reading.

An unforeseen and uncontrollable event that excuses a party to a contract from performing his or her duties under that contract. For example, a landlord can break a lease if the property she agreed to rent accidentally burns down before the tenants move in.

A right to use property, acquired by a long tradition of open and obvious use. For example, if hikers have been using a trail through your backyard for ten years and you've never complained, they probably have an easement by prescription through your yard to the trail.

A legal doctrine stating that if a person receives money or other property through no effort of his own, at the expense of another, the recipient should return the property to the rightful owner, even if the property was not obtained illegally. Most courts will order that the property be returned if the party who has suffered the loss brings a lawsuit.

A legally binding agreement involving two or more people or businesses (called parties) that sets forth what the parties will or will not do. Most contracts that can be carried out within one year can be either oral or written. Major exceptions include contracts involving the ownership of real estate and commercial contracts for goods worth $500 or more, which must be in writing to be enforceable. (See statute of frauds.) A contract is formed when competent parties -- usually adults of sound mind or business entities -- mutually agree to provide each other some benefit (called consideration), such as a promise to pay money in exchange for a promise to deliver specified goods or services or the actual delivery of those goods and services. A contract normally requires one party to make a reasonably detailed offer to do something -- including, typically, the price, time for performance and other essential terms and conditions -- and the other to accept without significant change. For example, if I offer to sell you ten roses for $5 to be delivered next Thursday and you say 'It's a deal,' we've made a valid contract. On the other hand, if one party fails to offer something of benefit to the other, there is no contract. For example, if Maria promises to fix Josh's car, there is no contract unless Josh promises something in return for Maria's services.