The expression "hip twirl" is an interpretation of the French expression "danse du ventre", which was connected to the move in the Victorian period, and most likely initially alluded to the Arabic tribe Ouled Nail artists of Algeria, whose move utilized more stomach developments than the moves portrayed today as "hip twirl". It is something of a misnomer, as all aspects of the body is included in te move; the most highlighted body part is typically the hips.
In Arabic, the move is known as "Raqs Sharqi" ("Eastern Dance") or "Raqs Beledi" ("Country Dance" or "People Dance").