The word ‘tutu’ has its origins in the theatre audience. Those who bought cheaper tickets sat in a section located in the lower part of the theatre. This area gave the patrons sitting there a different view than the rest of the audience; they could often see under the ballerinas’ skirts and see their bottoms. This led to a lot of talk and eventually, the French baby talk word for this part of the ballerina, “cucu,” became “tutu.” - Source
There is something absolutely charming about a garment named after a ballerina’s bottom.
The tutu is a ballet-specific bit of clothing; just as ballet began as a French courtly pastime, so did the skirts of ballerinas begin, as French courtly dress (source). However, as dance became a profession, the clothes used for it became more specialized, leaving the panniered skirts behind, passing through the romantic era of Degas’s flowing skirts, and ending today, with a combination of gentle floating confections and flat, glittering discs.
Ballet was a form of performance created by and for a wealthy group of people, and as such, it provided a stylized form of the clothing those people wore. Games often have professions based on the arts- bards are the most common (I think), followed shortly by dancers. When you’re planning a costume, consider who in your game world normally funds the performances, and the in-game history of the art; it is some combination of these two factors that will inform how your performer presents themself. For example, an Elven performer of a gnomish art for gnomish audiences would primarily be wearing gnomish clothes tailored to her frame- perhaps with a few Elven touches, depending on the relationships between the species, and whether the audience would find that refreshing, or a perversion, or a refreshing perversion. But the Elven touches would be almost certain if performing for an audience at home; especially things affected by modesty or sumptuary laws. If you’re a wandering performer, consider where you were trained before you wandered, and where you wander to and from; noble houses are just as spread out as peasant hamlets.
Image by Léon Comerre [Public domain], via Wikimedia Commons