Short version: Brand identity is the system of visual and verbal elements that represent a brand.
It can include the name, logo, color palette, typography, imagery, icons, layout rules, design details, tone of voice, messaging patterns, and sometimes motion or sound. These elements make the brand recognizable and help express what it stands for. Brand identity is what the company uses intentionally; brand perception is what people actually think and feel after encountering it.
A strong identity should fit the business strategy, audience, category, and level of trust the brand needs to create. It should also be usable in real life: website, social profiles, ads, documents, packaging, presentations, email, and product experience. If the identity only looks good in a mockup but breaks in daily use, it is not finished.
Related terms: visual identity, brand, and brand book.