The word usus was employed in the Roman civil law, and there meant a right to take so much of the fruit or profit of a thing as was needed for sustenance; while usufructu8 had a larger meaning, including a qualified right of possession. In the law of England and the United States, the word use has a precise meaning, which is similar to that of the Jidei commissum of the Roman law. It means a confidence reposed in one who has the property (or to whom it is given) in possession, that he will hold it for the use or benefit of another, who is called in Norman French the cestuy que use. A Roman magistrate (a preetor) was" charged with the enforcement of these Jidei commissa, and was called commissarius. "When uses became common in England, the chancellor, under whose jurisdiction they passed, had much the same duty to perform as the Roman commissarius; and indeed Lord Bacon calls this magistrate a Roman chancellor. - Uses were invented in England to avoid and defeat the statutes of mortmain (see Trust); and to protect those statutes against uses, the statute of 27 Henry VIII., commonly called the statute of uses, was enacted.

This provided that any person or corporation entitled to a use in fee simple, fee tail, or otherwise, should stand seized and possessed of the land itself, in the like estate which they had in the use; the intention being to subject a conveyance to the use of any one, and the property and the cestuy que use, to the same legal restraints and liabilities as if the conveyance had been made directly to the cestuy que use. This statute was said, in legal phraseology, "to execute the use." It was intended to prevent conveyances to use, by making them of no effect where they violated the statutes of mortmain, and of no more effect than a direct conveyance where they did not. Still such uses as the law permitted, or as courts of equity could protect, were found to be exceedingly convenient, and became common; and courts of equity retained their hold upon them, the person to whom the conveyance was made being considered as having the legal estate, subject to the rules of law and the jurisdiction of courts of law, while the cestuy que use has an equitable estate subject to the rules and the courts of equity.

This is now the prevailing condition of the law of uses in England and in the United States. But the whole system of law and of equity in regard to uses has become as intricate and extensive as it is important. Here we can do no more than indicate the principal rules of this system. - There can be no use, unless: 1, there is a person capable in law of taking it; 2, a person capable in law of being seized of the property to the use of the other; 3, an express declaration of use, or a consideration and a transfer or contract from which the court will imply a use; and 4, sufficient estate or property or interest to sustain a use. Then, if a use exists which the courts can recognize, it is descendible, or heritable, or devisable, or transferable according to the rules of law or equity, in conformity with the provisions in the instrument creating the use. If the cestuy que use of land be married, his widow has no dower, and the husband of a cestuy que use has no tenancy by courtesy, because the cestuy que use has no seisin, nor can he bring an action at law respecting it.

The seisin is in the feoffee-to-use, and while his legal estate is subject to all legal incidents at law, equity will subject all these legal incidents to the equitable requirements of the use. - Trusts and uses are often spoken of together, and from the article on Trusts their similarity or analogy will be seen. They differ however in important particulars.