A ball gown is the most formal female attire for social occasions. According to rules of etiquette, a ball gown must be worn where "evening dress" or "white tie" is specified on the invitation. It is a full-skirted gown reaching to the ankles (ballerina length) or to the floor (full-length ball gown), made of fine fabric, and expensively trimmed. Most ball gowns are cut off the shoulder and decollete (having a low neckline exposing part of the bosom); any version with straps, lapels or sleeves must at least expose the neckline. Such gowns are typically worn with a stole (a formal shawl in expensive fabric), cape or cloak in lieu of a coat, "good" (couture or vintage) jewellery and opera-length gloves. Standard accessories are dancing shoes and a clutch style evening bag. Where "state decorations" are to be worn, they are on a bow pinned to the chest, and married women wear a tiara if they have one.
The ball-gown shape has changed little since the mid-19th century. Fine natural fabrics are preferred, although today, man-made fabrics are acceptable. The most common fabrics for fine gowns are satin, silk, taffeta, chiffon and velvet trimmed in lace, pearls, sequins, embroidery, or ruffles.
The elements of ladies' white tie attire
The elements of ladies' white tie attire typically include:
- ball gown - full-length (to the floor)
- dancing shoes - formal high-heeled pumps or sandals, or ballet slippers
- jewellery - earrings and necklace; rings and bracelets are optional. A watch is not considered appropriate unless the face is covered so that it resembles a bracelet; these are often bejewelled versions
- gloves - should be opera length
- stole, cape or cloak, or an opera coat
- handbag - clutch style or small evening bag
- state decorations - if specified on invitation; worn on a bow pinned to the chest
- tiara - if "state decorations" are specified; worn by married women only
Ballgowns for specific occasions
- debutants wear white ball gowns at their “coming out” event, often known as a cotillion.
- Female invitees to a black and white ball wear white, black or bi-colour gowns
- A lady accompanying a gentleman wearing formal Scottish dress (a formal kilt) wears a white ball gown with a tartan sash.
- A lady may not wear a white gown to a wedding without being thought of as declassé.