So, at the risk of subjecting myself to some ridicule, I ask the assembled wordies:

What is a "hotbed?"

AHD gives us:

1. An environment conducive to vigorous growth or development, especially of
something undesirable: a hotbed of intrigue. 2. A glass-covered bed of soil
heated with fermenting manure or by electricity, used for the germination of
seeds or for protecting tender plants.

But do any of us ever use this word in any way other than in the "a hotbed of..." construction?