What is Brand?

'What is a brand? Too often even marketing professionals don't have an answer, and too many have their 'own' answer. Which makes life very confusing! We've trawled through our resources to find some of the best definitions:
The Dictionary of Business and Management defines a brand as:

"a name, sign or symbol used to identify items or services of the seller(s) and to differentiate them from goods of competitors."
Signs and symbols are part of what a brand is, but to us this is a very incomplete definition.
Walter Landor, one of the greats of the advertising industry, said:
"Simply put, a brand is a promise. By identifying and authenticating a product or service it delivers a pledge of satisfaction and quality."
In his book 'Building Strong Brands' David Aaker suggests the brand is a 'mental box' and defines brand equity as:
"A set of assets (or liabilities) linked to a brand's name and symbol that adds to (or subtracts from) the value provided by a product or service…"
This is an important point: brands are not necessarily positive!
Building from this idea of a 'mental box', a more poetic definition might be:

"A brand is the most valuable real-estate in the world, a corner of the consumer's mind."
These are all great definitions, but we believe the best is this:

"A brand is a collection of perceptions in the mind of the consumer."
Why is it best? Well, first of all it is easy to remember, which is always useful! But it is also best because it works to remind us of some key points:
This definition makes it absolutely clear that a brand is very different from a product or service. A brand is intangible and exists in the mind of the consumer.
This definition helps us understand the idea of brand loyalty and the 'loyalty ladder'. Different people have different perceptions of a product or service, which places them at different points on the loyalty ladder.
This definition makes it clear how to build a brand. A brand is built not only through effective communications or appealing logos. A brand is built through the total experience that it offers.