from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A smooth, hard, dark-colored panel for writing on with chalk.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A large flat surface, finished with black slate or a similar material, that can be written upon with chalk and subsequently erased; a chalkboard
- v. To use a blackboard to assist in an informal discussion.
from the GNU version of the Collaborative International Dictionary of English
- n. A broad board painted black, or any black surface on which writing, drawing, or the working of mathematical problems can be done with chalk or crayons. It is much used in schools. In late 20th century similar boards of a green slate as well as some colored white became common; wrioting on the slate bioards may be done with chalk, but writing on the white boards is done with colored pens, such as grease pens, which leaves a trace that can be easily erased. The newer boards, usualy called chalkboards are nevertheless still sometimes referred to as blackboards.
from The Century Dictionary and Cyclopedia
- n. A board painted black, used in schools, lecture-rooms, etc., for writing, drawing, or ciphering with chalk.
- n. Hence Any prepared surface, as of plaster or slate, used for the same purpose.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. sheet of slate; for writing with chalk
From black + board, because such surfaces were once typically made of black slate. (Wiktionary)