† swap thakSc.Obs. [f. swap v. in the Sc. sense of ‘to gird’ + thack n.] ‘Thin boards of wood firmly fastened over a thatched roof, as a girding for the thatch’ (Jam.). 1496Acc.Ld. High Treas.Scot. I. 310 Item, to the sawaris, for swap thak sawing to the samyn hous,..xxx s.