The term ballerina is originally meant as the rank of a principal female dancer in a ballet company. When it was originally used, this meant that not every female dancer in the ballet company was considered a ballerina, and instead by their rank or simply as “a ballet dancer”. Today, a leading female ballet dancer is usually simply called a “principal dancer.”
Since it is more commonly used today, the term has lost its prestige. Many mothers will reference their 6 year old daughter as “mommy’s little ballerina” and usually every woman that is part of a ballet company is referred to as a ballerina.