What is Brand Loyalty?

Legal Definition
Brand loyalty is defined as positive feelings towards a brand and dedication to purchase the same product or service repeatedly now and in the future from the same brand, regardless of a competitor’s actions or changes in the environment. It can also be demonstrated with other behaviours such as positive word of mouth advocacy. Brand loyalty is where an individual buys products from the same manufacturer repeatedly rather than from other suppliers. Businesses whose value rests in a large part on their brand loyalty are said to use the loyalty business model.
-- Wikipedia
Legal Definition
The situation in which a consumer generally buys the same manufacturer-originated product or service repeatedly over time rather than buying from multiple suppliers within the category (sales promotion definition).