ˈinˌsēm noun
Etymology: in- (II) + seam
: an inner seam: as
a. : the seam from the crotch to the leg bottom of trousers
b. : a seam showing on the inside only used for articles (as gloves) often made without outside seams
c. : a hidden seam in a welt shoe fastening the welt, lining, and shoe upper to the insole