1382, "a roofing slate," from O.Fr.
esclat "split piece, splinter," back-formation from
esclater "to break, splinter, burst," probably from Frank.
*slaitan "to tear, slit," related to O.H.G.
slizan, O.E.
slitan (see
slit). Meaning "long, thin, narrow piece of wood or metal" attested from 1764.