These words are comparable when they mean to make something larger or greater. Enlarge points to size or dimension: to enlarge a photograph; to enlarge a house by adding a new wing; to enlarge a staff by engaging six new people. Increase may point to quantity or intensity as well as size: to increase one’s stock of food during wartime.

• Melting snow increases the flow of water in many streams during spring thaws; The safety of cars has been increased by the addition of seat belts and collapsible steering columns.

In other senses, increase may mean to grow in number: May your followers increase . Or to step up or accelerate: to increase the rate of productivity.

Expand may mean to increase in range, scope or volume as well as in size: to expand the economy by introducing government spending on a broad scale. Expand conveys the idea of a general enlarging in all dimensions rather than one, and suggests an unfolding or opening out: to expand one’s operation to include all aspects of the clothing business. Expand also can refer to the filling in or development of details: to expand a speech; to expand an equation. Amplify can also refer to the filling in of details, but stresses the addition of material for the sake of completeness, as by illustration.

• The Minister was asked to amplify his statement that our goal was nothing less than total victory; to amplify a comment by providing reporters with back ground information.

As the contexts of these illustrations indicate, amplify is most often used of formal situations. In its more basic sense, amplify is nowadays used almost exclusively to refer to the increase in the strength of sound or of the electromagnetic waves that produce it: to amplify sound with the use of electronic equipment.

Augment means to add to, and is in some contexts interchangeable with increase or enlarge : to augment (or increase or enlarge ) a sales force. Augment , however, emphasizes the action of addition more than the increase in size, and often suggests that the addition is temporary expedient rather than a permanent or structural increase : to augment a besieged infantry regiment with fresh troops. Augment may refer to intensity as well as amount: to augment an electrical signal by increasing the power, thus amplifying the sound.

Magnify means to make something larger or greater either in fact or in appearance: A microscope magnifies objects by making them appear larger even though it does not increase their actual sizes. Sometimes magnify implies exaggeration ?that is, making something appear to be larger or more important than it really is: to magnify a relatively trivial loss.