"invited by the Miss Bertrams to join in a glee, she tripped off to the instrument"
'Singing to the Reverend' (Late Victorian depiction of early 19th century scene)
Public Domain'Singing to the Reverend' (Late Victorian depiction of early 19th century scene) - Credit: Edmund Blair Leighton

 A glee is a part song arranged for three or more voices, usually sung unaccompanied. Glees were generally intended for male voices, although they sometimes included a soprano part that might be sung by women. They were particularly popular between the mid 18th and the mid 19th centuries.

Unusually, here the suggestion is that the glee is to be sung to piano accompaniment, and by female voices.

 

Listen here and here to some glee music.