Word request for 'visual style guide' / 'visual nomenclature' / 'visual system'

Question

What do you call a system of what visual items mean? Visual items include symbols but also line thickness, color, etc. It could be used for either production or consumption of a designed piece.

For example, you are designing a book and you want a consistent use of typefaces and lines throughout the book. A certain font always means an explanation, another means citation; a certain line always means movement, another means causation. This is standard practice but I can't think of the word.

The word could refer to a physical rulebook of sorts, or just to the visual system even if its never written out anywhere.

"I developed a ____ for the website so that all the designers would make a consistent product and so that readers would easily understand what everything means."

Possibilites

• Visual style guide works a) I believe a better word exists that I am forgetting and b) it seems to refer more to a rule book than to a system.
• Visual system is too vague.
• Visual nomenclature is perhaps the closest by way of analogy. Is there anything that wouldn't require visual in front? Also, nomenclature might not make sufficient reference to an internal logic.

Answer 1

"Presentation schema" has the intended meaning. While that does sound technical, it seems this article is intended for people with some knowledge of software design.

I developed a uniform presentation schema for the website such that all designers would make a consistent product and all readers would intuitively understand the meaning of each page."

Answer 2

Perhaps Brand Guidelines is what you are thinking of:

Brand Guidelines

• Essentially a set of rules that explain how your brand works. (also commonly referred to as “brand standards”, “style guide” or “brand book”)

These guidelines typically include basic information such as:

1. An overview of your brand’s history, vision, personality and key values.
2. Brand message or mission statement – including examples of ‘tone of voice’.
3. Logo usage – where and how to use your logo including minimum sizes, spacing and what not to do with it.
4. Colour palette – showing your primary and secondary colour palettes with colour breakdowns for print, screen and web.
5. Type style – showing the specific font that you use and details of the font family and default fonts for web use.
6. Image style/photography – examples of image style and photographs that work with the brand.
7. Business card and letterhead design – examples of how the logo and font are used for standard company literature.

(NiftyMarketing)