Lath

n.; pl. LĀTHĀ (lāthz). [A-S. lattu, for laddu, O. H. Ger. latta, lata, N. H. Ger. latte, D. lat; whence Fr. latte, It. latta, Pr., Sp., & Pg. latta. Cf. W. llāth, a rod, staff, yard.]

1. A thin, narrow board, or slip of wood, to be nailed to the rafters of a building, for the purpose of supporting the tiles, or covering.
2. A thin, narrow slip of wood, to be nailed to the studs, for the purpose of supporting the plastering.