An objective, in the sense of an end in view, a result to be accomplished, is manifestly an objective in mind. As already indicated (page 36), however, military usage also assigns to the term "objective" an additional meaning, a meaning exclusively concrete. Results in war are attained through the actual or threatened use of physical force (pages 8 and 9) directed with relation to something tangible, such as, for example, some physical element of the enemy's strength. Action as to this tangible feature (e.g., if it is destroyed, occupied, neutralized, or otherwise dealt with) will result in, or further the attainment of, an effect desired. Thus the physical objective occupies a sharply defined position in warfare, in that it establishes the physical basis of the objective and indicates the geographical direction of the effort. Since the physical objective is always an object--be it only a geographical point--, it is more than a mental concept; it is an objective in space. For example, the objective being "the destruction of the enemy battleship", the physical objective is the enemy battleship. As used herein the expression "the objective" or "the military objective" (page 55), when unqualified, ordinarily indicates the mental objective. The term is properly applicable to a physical objective when the context makes the meaning clear. Ordinarily, and always when clarity demands, a tangible focus of effort is herein denoted a "physical objective". Military Operations. Appropriate action to create or maintain a situation will take the form of a military operation. An operation, in the basic sense, is merely an act, or a series of acts. The word is derived from the Latin opus, meaning "work". A military operation is therefore an act, or a series of included acts (i.e., work), of a military character. A military operation may consist of an entire campaign, or even of several such, constituting a clearly defined major stage in a war; or such an operation may consist of portions thereof. The term is also applied, properly, to entire series of acts on the part of successive commands, from the higher to the lower echelons, to and including distinctive military actions which relate to the merest routine. A plan of action to attain a military objective is, therefore, a plan of military operations, including supporting measures (see page 167), considered or adopted as a method of procedure for the achievement of that end (see page 21). Such a plan or method of procedure requires action with relation to correct physical objectives in such a manner as to attain the objective, i.e., to maintain the existing situation or to create a new one, conformably to the appropriate effect desired.