'Hotbed' definitions:

Definition of 'hotbed'

From: WordNet
noun
A situation that is ideal for rapid development (especially of something bad); "it was a hotbed of vice"
noun
A bed of earth covered with glass and heated by rotting manure to promote the growth of plants

Definition of 'Hotbed'

From: GCIDE
  • Hotbed \Hot"bed`\, n.
  • 1. (Gardening) A bed of earth heated by fermenting manure or other substances, and covered with glass, intended for raising early plants, or for nourishing exotics. [1913 Webster]
  • 2. A place which favors rapid growth or development; as, a hotbed of sedition. [1913 Webster]