What is Slate?

Slate definition and meaning on Dictionary terms:
a fine-grained rock formed by the metamorphosis of clay, shale, etc., that tends to split along parallel cleavage planes, usually at an angle to the planes of stratification.
a thin piece or plate of this rock or a similar material, used especially for roofing or as a writing surface.
a dull, dark bluish gray.

a list of candidates, officers, etc., to be considered for nomination, appointment, election, or the like.

verb (used with object), slat