Yeah, me either. But there is. I found it in the dictionary this week while I was looking something else.
If you're interested, Gresham's Law, according to the dictionary, is an observation in economics that states when two coins are equal in debt-paying value but unequal in intrinsic value, the one having the lesser intrinsic value tends to remain in circulation and the other to be hoarded or exported as bullion. Broadly, it is any process by which inferior products or practices drive out superior ones.
Since this discovery was so enlightening and exciting, I've decided I may undertake reading Merriam-Webster's Collegiate Dictionary cover to cover. I'll let you know how that project goes...ha!