The difference between Expansion and Increase

When used as nouns, expansion means the act or process of expanding, whereas increase means an amount by which a quantity is increased.

Increase is also verb with the meaning: (of a quantity, etc.) to become larger or greater.

check bellow for the other definitions of Expansion and Increase

Expansion as a noun:

The act or process of expanding.

Examples:

"The expansion of metals and plastics in response to heat is well understood."
Expansion as a noun:

The fractional change in unit length per unit length per unit temperature change.
Expansion as a noun:

A new addition.

Examples:

"My new office is in the expansion behind the main building."
Expansion as a noun:

A product to be used with a previous product.

Examples:

"This expansion requires the original game board."
Expansion as a noun:

That which is expanded; expanse; extended surface.
Expansion as a noun (steam engines):

The operation of steam in a cylinder after its communication with the boiler has been cut off, by which it continues to exert pressure upon the moving piston.

Increase as a verb (intransitive):

(of a quantity, etc.) To become larger or greater.

Examples:

"His rage only increased when I told him of the lost money."
Increase as a verb (transitive):

To make (a quantity, etc.) larger.
Increase as a verb:

To multiply by the production of young; to be fertile, fruitful, or prolific.
Increase as a verb (astronomy, intransitive):

To become more nearly full; to show more of the surface; to wax.

Examples:

"The Moon increases."

Increase as a noun:

An amount by which a quantity is increased.
Increase as a noun:

For a quantity, the act or process of becoming larger
Increase as a noun (knitting):

The creation of one or more new stitches; see .