It's worth noting this is normal in language. Consider the highly non-technical English "lighthouse," which has acquired a far more specific meaning than "a hou

It's worth noting this is normal in language. Consider the highly non-technical English "lighthouse," which has acquired a far more specific meaning than "a house made of light" or "a house that produces light" or "a house that weighs very little." I'm not familiar with "blackboard" being a valid term for any board that is black, but specifically one used in pairing with chalk to be written on. etc.