The Regency Wardrobe collection - research - The Mameluke Sleeve

https://www.ngv.vic.gov.au/explore/collection/work/50824/

See: https://military.wikia.org/wiki/Mamluk

"...Mamelukes are members of a former military caste originally composed of slaves from Turkey, that held the Egyptian throne from the mid thirteenth century to the early 1500s. They remained strong until 1811. Regency fashion took inspiration from Mameluke clothing..."

After 1808 Spanish ornament featured on robes and appeared as slashed areas and tiered sleeves. When sleeves covered the hand they were called à la mamelouk. Image examples here illustrate this extra long sleeve length.

The Napoleonic Wars meant that a soldier's uniform had high visibility and military style details featured on clothing for both sexes.

Frogging, braids, cords, velvet and other trims lent a topical jaunty dashing air to many a garment, especially outdoor wear.

Peasant influence from European dress was particularly applied to the name of coats, cloaks and mantles such as the Witzchoura redingote an empire cloak of Russian origin". - https://www.fashion-era.com/regency_fashion.htm

But this same design in sleeves seems also to have been known as the Marie sleeve (after Marie Antoinette) - sometimes referred to as the Juliet sleeve - it seems there is no final concensus as to whether there were differences between the Mameluke and Marie but for more on this debate please see: https://janeaustensworld.wordpress.com/2010/04/22/mamaluke-or-marie-sleeves-on-regency-dresses/