Noun

(en noun)

An original object or form which is a basis for other objects, forms, or for its models and generalizations

An early sample or model built to test a concept or process

The prototype had loose wires and rough edges, but it worked.

(semantics) An instance of a category or a concept that combines its most representative attributes.

A robin is a prototype of a bird; a penguin is not.

(computing) A declaration of a function that specifies the name, return type, and parameters but none of the body, or actual code.

Noun

(en noun)

The act of illustrating; the act of making clear and distinct; education; also, the state of being illustrated, or of being made clear and distinct.

That which illustrates; a comparison or example intended to make clear or apprehensible, or to remove obscurity.

* {{quote-news

, year=2012 , date=June 19 , author=Phil McNulty , title=England 1-0 Ukraine , work=BBC Sport citation , page= , passage=England will regard it as a measure of justice for Frank Lampard's disallowed goal against Germany in Bloemfontein at the 2010 World Cup - but it was also an illustration of how they rode their luck for long periods in front of a predictably partisan home crowd.}}

A picture designed to decorate a volume or elucidate a literary work.

A calculated prevision of insurance premiums and returns (life insurance)"an illustration [...] is a computer projection of future premiums, cash values and death benefits based on the current dividend scale (whole life) or current interest rates and current costs of insurance (universal life)." taken from http://www.evaluatelifeinsurance.org