s embracing all the territory
we seek to take possession of or to defend.

A truer definition is, "the area, whether of sea or land or both, within
which the enemy must be overpowered before we can secure the object of the
particular operation."

Consequently, since the nature of the war varies with the object, it may be
defensive in one theatre of operations and offensive in another.

Where the operations are defensive in character any special movement or
movements may be offensive.

OBJECTIVE

An objective is "any point or force against which an offensive movement is
directed." Thus where the _object_ in any theatre of operation is to get
command of a certain sea in which the enemy maintains a fleet, that fleet
will usually be the _objective_.

LINES OF OPERATION

A line of operation is "the area of land or sea through which we operate
from our base or starting point to reach our objectives."

Lines of operation may be exterior or interior. We are said to hold the
interior lines when we hold such a position, in regard to a theatre of
operations, that we can reach its chief objective points, or forces, more
quickly than the enemy can move to their defence or assistance. Such a
position is called an interior position. "Exterior Lines" and "Exterior
Position" are the converse of these.

LINES OF COMMUNICATION

This expression is used of three different things:--

(1) _Lines of supply_, running from the base of operations to the point
which the operating force has reached.

(2) _Lines of lateral communication_ by which several forces engaged in
one theatre of operations can communicate with each other and move to
each other's support.

(3) _Lines of retreat_, which are lines of supply reversed, _i.e._,
leading back to the base.

These three ideas are best described by the term "lines of passage and
communication," which we had in use at the end of the eighteenth century.

Ashore, lines of passage and communication are roads, railways, waterways,
&c.

At sea, they may be regarded as those waters over which passes the normal
course of vessels proceeding from the base to the objective or the force to
be supplied.

In Land Strategy the great majority of problems are problems of
communication. Maritime Strategy has never been regarded as hinging on
communications, but probably it does so even more than Land Strategy, as
will appear from a consideration of maritime communication