undersleeve

un·der·sleeve

 (ŭn′dər-slēv′)
n.
1. A sleeve worn under another.
2. An ornamental sleeve worn under another sleeve, designed to extend below or show through slashes in the outer sleeve.

undersleeve

(ˈʌndəˌsliːv)
n
(Clothing & Fashion) the lower of two sleeves
References in periodicals archive ?
Sleeve linings of rich fabrics or even fOr were displayed by wide turn-ups; detachable, ermine-lined undersleeves were also used at ceremonies such as the coronation.