c.1340, from O.Fr. esclate,
fem. of esclat
"split piece, splinter" (Fr. éclat
, see slat
), so called because the rock splits easily into thin plates. As a color, first recorded 1882. Sense of "a writing tablet" (made of slate), first recorded c.1391, led to that of "list of candidates," first recorded 1842. The verb meaning "propose, schedule" is recorded from 1883; sense of "nominate" is attested from 1804. Clean slate
(1868) originally referred to scores chalked up in a tavern.