A large flat surface, finished with black slate or a similar material, that can be written upon with chalk and subsequently erased; a chalkboard.
To use a blackboard to assist in an informal discussion.
Any carved or engraved surface.
The central core of a plant's root and stem system, especially including the vascular tissue and developed from the plerome.
An upright (or formerly upright) slab containing engraved or painted decorations or inscriptions; a stela.