from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A panel covered with white, glossy plastic for writing on with erasable markers.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A large vertical writing area, finished with a hard white material, which can be written upon using special markers and subsequently erased.
white + (black)board.(American Heritage® Dictionary of the English Language, Fourth Edition)
From white + board, modelled on blackboard. (Wiktionary)