The document discusses different definitions of what a brand is from experts in marketing and business. It argues that the best definition is "a brand is the sum of all the associations consumers have about your offering" because it is actionable, reflecting how the brain forms memories and associations, and brands with strong associations are more salient. The document outlines how understanding consumers' brand associations can help build desired associations through marketing to create preference and loyalty. It identifies 26 universal sources of associations that can be systematically explored to develop distinctive brand positions.