Definitions:
a fine-grained grey, green, or bluish-purple metamorphic rock easily split into smooth, flat plates

a flat plate of slate formerly used for writing on in schools

a bluish-grey colour

a list of candidates for election to a post or office, typically a group sharing a set of political views

a board showing the identifying details of a take in a film, held in front of the camera at the beginning and end of the take

cover (something, especially a roof) with slates

criticize severely

schedule; plan

identify (a take in a film) using a slate