What is identity design?

One major role in the ‘brand’ or ‘corporate image’ of a company is its identity.
In most cases, identity design is based around the visual devices used within a company, usually assembled within a set of guidelines. These guidelines that make up an identity usually administer how the identity is applied throughout a variety of mediums, using approved colour palettes, fonts, layouts, measurements and so forth. These guidelines ensure that the identity of the company is kept coherent, which in turn, allows the brand as a whole, to be recognisable.
The identity or ‘image’ of a company is made up of many visual devices:

• A Logo (The symbol of the entire identity & brand)
• Stationery (Letterhead + business card + envelopes, etc.)
• Marketing Collateral (Flyers, brochures, books, websites, etc.)
• Products & Packaging (Products sold and the packaging in which they come in)
• Apparel Design (Tangible clothing items that are worn by employees)
• Signage (Interior & exterior design)
• Messages & Actions (Messages conveyed via indirect or direct modes of communication)
• Other Communication (Audio, smell, touch, etc.)
• Anything visual that represents the business.

All of these things make up an identity and should support the brand as a whole. The logo however, is the corporate identity and brand all wrapped up into one identifiable mark. This mark is the avatar and symbol of the business as a whole.