Hines Land Use & Zoning Lawyer, Minnesota, page 4

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.

(1) A legal principle that prevents a person from asserting or denying something in court that contradicts what has already been established as the truth. equitable estoppelA type of estoppel that bars a person from adopting a position in court that contradicts his or her past statements or actions when that contradictory stance would be unfair to another person who relied on the original position. For example, if a landlord agrees to allow a tenant to pay the rent ten days late for six months, it would be unfair to allow the landlord to bring a court action in the fourth month to evict the tenant for being a week late with the rent. The landlord would be estopped from asserting his right to evict the tenant for late payment of rent. Also known as estoppel in pais.estoppel by deedA type of estoppel that prevents a person from denying the truth of anything that he or she stated in a deed, especially regarding who has valid ownership of the property. For example, someone who grants a deed to real estate before he actually owns the property can't later go back and undo the sale for that reason if, say, the new owner strikes oil in the backyard.estoppel by silenceA type of estoppel that prevents a person from asserting something when she had both the duty and the opportunity to speak up earlier, and her silence put another person at a disadvantage. For example, Edwards' Roofing Company has the wrong address and begins ripping the roof from Betty's house by mistake. If Betty sees this but remains silent, she cannot wait until the new roof is installed and then refuse to pay, asserting that the work was done without her agreement.estoppel in paisSee equitable estoppel.promissory estoppelA type of estoppel that prevents a person who made a promise from reneging when someone else has reasonably relied on the promise and will suffer a loss if the promise is broken. For example, Forrest tells Antonio to go ahead and buy a boat without a motor, because he will sell Antonio an old boat motor at a very reasonable price. If Antonio relies on Forrest's promise and buys the motorless boat, Forrest cannot then deny his promise to sell John the motor at the agreed-upon price.(2) A legal doctrine that prevents the relitigation of facts or issues that were previously resolved in court. For example, Alvin loses control of his car and accidentally sideswipes several parked cars. When the first car owner sues Alvin for damages, the court determines that Alvin was legally drunk at the time of the accident. Alvin will not be able to deny this fact in subsequent lawsuits against him. This type of estoppel is most commonly called collateral estoppel.

A proposal to enter into an agreement with another person. An offer must express the intent of the person making the offer to form a contract, must contain some essential terms--including the price and subject matter of the contract--and must be communicated by the person making the offer. A legally valid acceptance of the offer will create a binding contract.

A determination of the value of something, such as a house, jewelry or stock. A professional appraiser -- a qualified, disinterested expert -- makes an estimate by examining the property, and looking at the initial purchase price and comparing it with recent sales of similar property. Courts commonly order appraisals in probate, condemnation, bankruptcy or foreclosure proceedings in order to determine the fair market value of property. Banks and real estate companies use appraisals to ascertain the worth of real estate for lending purposes. And insurance companies require appraisals to determine the amount of damage done to covered property before settling insurance claims.

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.

Insurance that reimburses a mortgage lender if the buyer defaults on the loan and the foreclosure sale price is less than the amount owed the lender (the mortgage plus the costs of the sale). A home buyer who makes less than a 20% down payment may have to purchase PMI.

A tax imposed by a state to compensate for the sales tax lost when an item is purchased outside of the state, but is used within the state. For example, you buy your car in a state that has no sales tax, but you live across the border in a state that does have a sales tax. When you bring your car home and register it in your state, the state taxing authority will bill you for the sales tax it would have collected had you bought the car within the state.