Question

introductory lines for fancy dress competition costumes of world Russia

Answer 1

Costume is the distinctive style of dress of an individual or group that reflects their class, gender, profession, ethnicity, nationality, activity or epoch.
The term also was traditionally used to describe typical appropriate clothing for certain activities, such as riding costume, swimming costume, dance costume, andevening costume. Appropriate and acceptable costume is subject to changes in fashion and local cultural norms.[1]

"But sable is worn more in carriages, lined with real lace over ivory satin, and worn over some smart costume suitable for an afternoon reception." A Woman's Letter from London(23 November 1899).