ax·i·om

– noun
1. a self-evident truth that requires no proof.
2. a universally accepted principle or rule.
3. a proposition that is assumed without proof for the sake of studying the consequences that follow from it.

cli·ché

– noun
1. a trite, stereotyped expression; a sentence or phrase, usually expressing a popular or common thought or idea, that has lost originality, ingenuity, and impact by long overuse.
2. a trite or hackneyed plot, character development, use of color, musical expression, etc.
3. anything that has become trite or commonplace through overuse.

ar·che·type

– noun
1. the original pattern or model from which all things of the same kind are copied or on which they are based; a model or first form; prototype; quintessence.
2. a collectively inherited unconscious idea, pattern of thought, image, etc., universally present in individual psyches.