top crease of a sleeve (traditional Japanese clothing)
Refers to the raised seam or crease at the shoulder end of a sleeve in kimono, yukata, and similar garments.
The top crease of the kimono sleeve is neatly set.
sleeve cap (Western clothing)
In tailoring, the curved upper part of a set-in sleeve that joins the armhole; a technical term.
This jacket doesn't have enough ease in the sleeve cap.
Compound of 袖 (sode, 'sleeve') and 山 (yama, 'mountain'), referring to the raised, mountain-like shape at the top of a sleeve.