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