Dryden Landlord-Tenant Lawyer, New York

The causing of harm by disrupting something that belongs to someone else -- for example, interfering with a contractual relationship so that one party fails to deliver goods on time.

A lawsuit brought by two parties, not as adversaries, but as collaborators in order to resolve a legal question that affects them both. For example, two companies might bring a friendly suit to court in order to clarify a legal interpretation of a contract between them.

An arrangement designed to encourage low-and moderate-income families to purchase housing, in which the housing is offered at an extremely favorable price with a low down payment. The catch is that when the owner sells, she gets none of the profit if the market value of the unit has gone up. Any profit returns to the organization that built the home, which then resells the unit at an affordable price.

A legal doctrine that prevents a plaintiff who has acted unethically in relation to a lawsuit from winning the suit or from recovering as much money as she would have if she had behaved honorably. For example, if a contractor is suing a homeowner to recover the price of work he did on the home, his failure to perform the work as specified would leave him with unclean hands.

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.

A legal claim placed on real estate by someone who is owed money for labor, services or supplies contributed to the property for the purpose of improving it. Typical lien claimants are general contractors, subcontractors and suppliers of building materials. A mechanics' lien claimant can sue to have the real estate sold at auction and recover the debt from the proceeds. Because property with a lien on it cannot be easily sold until the lien is satisfied (paid off), owners have a great incentive to pay their bills.

An exception to a zoning ordinance, usually granted by a local government. For example, if you own an oddly shaped lot that could not accommodate a home in accordance with your city's setback requirement, you could apply at the appropriate office for a variance allowing you to build closer to a boundary line.

A means by which one can legally take another's property without paying for it. The requirements for adversely possessing property vary between states, but usually include continuous and open use for a period of five or more years and paying taxes on the property in question.

A contract giving written permission to use an invention, creative work or trademark. A license provides a way to make money from your invention or creative work without having to manufacture and sell copies yourself. By licensing an invention or work to a company, you get money (often in the form of royalties) in return for allowing the company to use, produce and sell copies of your invention or work in the marketplace.