There are as many definitions of 'brand' as there are brand managers and marketing 'consultants'.
Your logo is not your brand.
Let's say that again: your logo is not your brand.
Your branding, or visual identity, is absolutely a component of your brand - it should be a visual translation, a reminder, of your brand promise and the experience, but it is not the sum of your brand.
If you develop a logo and do not think about the product market fit, do not think about the path to purchase, you have developed a logo, not a brand.
If you develop a core colour palette and do not think about how to craft and deliver your message, you have developed a set of colours, not a brand.
If you think about how to construct an ad and do not think about how to make the experience exceed your customers' expectations, you have built an ad, not a brand.
Your brand is not your product or your name.
Your brand might include attributes of your product, but it is more than that. It is intangible and linked to subjective qualities.
A new veneer is not your brand.
Changing your branding, especially your visual identity, won't make your business different. It is essentially a new veneer on your house, but the walls of the house and the experience inside remains the same.
Your brand is the promise to the customer.
It is the sum of their experiences and knowledge of your brand.
Your customer defines it, but you can influence it.
You can influence your brand (the promise and the perception) through the triggers and levers of branding, of which visual identity is one lever.
You can influence your brand through the language you use and the tone and personality you use when you write your ads and content.
You can influence your brand through the channels you use to communicate and advertise.
You can influence your brand through those who speak on your behalf to their audience.
Brand marketing standards are evolving as we develop more understanding of how to influence and shape perception of brand. The most important precept to remember of course is that your reality and perception need to sync - this isn't about a false veneer or 'fake news' - do the right thing by your customers and your brand will become more meaningful.
The experts say it best
“A brand is no longer what we tell the consumer it is -- it is what consumers tell each other it is.” – Scott Cook
"Your brand is what other people say about you when you're not in the room." - Jeff Bezos