BT Šab 119a(22) :אותבה בסדיניה ואמרי לה בסייאניה דרישיה‏ : he placed it in his sheet, though some say of it that it was in his head's s'-cap
See the entire entry for səḏīn, səḏīnā n.m. linen sheet

BT Šab 119a(22) :בסייאניה דרישיה‏ : the s'-cap of his head
See the entire entry for syān, syānā n.m. skull-cap