slate 
(slāt)
(slāt)n.
1. A fine-grained metamorphic rock that splits into thin, smooth-surfaced layers.
2.
a. A piece of this rock cut for use as roofing or surfacing material or as a writing surface.
b. A writing tablet made of a similar material.
3. A record of past performance or activity: start over with a clean slate.
4. A list of the candidates of a political party running for various offices.
5. A dark or bluish gray to dark bluish or dark purplish gray.
adj.
1. Made of a fine-grained metamorphic rock: a slate roof.
2. Of the color slate.
tr.v. slat·ed, slat·ing, slates
1. To cover (a roof, for example) with slate.
2. To put on a list of candidates.
3. To schedule or designate: Our professor has slated the art history lecture for Thursday afternoon; was slated to direct the studio's next film.
[Middle English sclate, from Old French esclate, splinter, feminine of esclat; see SLAT.]