A person who feels loyalty to a nation, cause, or person feels a sense of allegiance, commitment, dedication toward them.
Loyalty is — you guessed it! — the quality of being loyal. People demonstrate their loyalty to a sports team by cheering for it, win or lose. People demonstrate their loyalty to a political party by voting only for the people of that party. Brand loyalty is the notion (or hope) that once consumers identify strongly with a particular brand or product, like a car or computer, they'll stick with that brand or maker when it comes time to buy new products.