The Collaborative International Dictionary of English v.0.48:
Lath \Lath\, n.; pl. Laths. [OE. laththe, latthe, latte, AS.
l[ae]tta; akin to D. lat, G. latte, OHG. latta; cf. W. llath
a rod, staff, yard. Cf. Lattice, Latten.]
A thin, narrow strip of wood, nailed to the rafters, studs,
or floor beams of a building, for the purpose of supporting
the tiles, plastering, etc. A corrugated metallic strip or
plate is sometimes used.
Lath brick, a long, slender brick, used in making the floor
on which malt is placed in the drying kiln.
Lath nail a slender nail for fastening laths.