Order (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. "origin"), a row or series, hence grade, class or rank, succession, sequence or orderly arrangement; from these, the original meanings of ordo, have developed the numerous applications attached to the word, many, if not most, of which appear in classical and medieval Latin. In the sense of a class or body of persons or things united by some common status, rank or distinguishing characteristics, or as organized and living under some common rules and regulations, we find the term applied, in such expressions as "lower" or "higher orders," to the class divisions of society; to the various grades of persons exercising spiritual functions in the Christian church (see Holy Order, below); to the bodies of persons bound by vows to a religious life (see Monasticism, and separate articles on the chief religious orders); to the military and monastic fraternities of the middle ages, such as the Templars, Hospitallers, &c., and to those institutions, founded by sovereigns or states, in part imitation of these fraternities, which are conveniently divided into orders of knighthood, or orders of merit (see Knighthood). The term "order" is thus used, in an easily transferred sense, for the various insignia, badge, star, collar, worn by the members of the institution. As applied to a group of objects, an "order" in zoological, botanical and mineral classification ranks next below a "class," and above a "family." The use of the word in architecture is treated in a separate article below.
The word has several technical mathematical usages. In number-theory it denotes a relative rank between the elements of an aggregate so that the collection becomes an ordered aggregate (see Number). The order of a plane curve is the number of points (real or imaginary) in which the curve is intersected by a straight line; it is equal to the degree (or coefficient of the highest power) of the Cartesian equation expressing the curve. The order of a non-plane curve is the number of points (real or imaginary) in which the curve intersects a plane (see Curve). The order of a surface is the number of points in which the surface intersects a straight line. For the order of a congruence and complex see Surface. The order of a differential equation is the degree of its highest differential coefficient (see Differential Equation).
Another branch of the sense-development of the word starts from the meaning of orderly, systematic or proper arrangement, which appears in the simplest form in such adverbial expressions as "in order," "out of order" and the like. More particular instances are the use of the word for the customary procedure observed in the conduct of the business of a public meeting, or of parliamentary debates, and for the general maintenance and due observance of law and authority, "public order." In liturgical use "order" is a special form of divine service prescribed by authority, e.g. the "Order of Confirmation," in the English Prayer Book.
The common use of "order" in the sense of a command, instruction or direction is a transference from that of arrangement in accordance with intention to the means for attaining it. It is a comparatively late sense-development; it does not appear in Latin, and the earliest quotations in the New English Dictionary are from the 16th century. Particular applications of the term are, in commercial usage, to a direction in writing to a banker or holder of money or goods, by the person in whom the legal right to them lies, to pay or hand over the same to a third person named or to his order. A bill or negotiable instrument made "payable to order" is one which can be negotiated by the payee by endorsement. At common law a negotiable instrument must contain words expressly authorizing transfer. By the Bills of Exchange Act 1882, § 8, "a bill is payable to order which is expressed to be so payable, or which is expressed to be payable to a particular person, and does not contain words prohibiting transfer or indicating an intention that it should not be transferable." Other applications are to a direction for the supply of goods and to a pass for free admission to a place of amusement, a building, &c.
In law an "order of the court" is a judicial direction on matters outside the record; as laid down by Esher, M.R., in Onslow v. Inland Revenue, 59, L.J.Q.B. 556, a "judgment" is a decision obtained in an action and every other decision is an "order." For "Order in Council" see below.