thunderhead
- n a rounded projecting mass of a cumulus cloud with shining edges; often appears before a thunderstorm
- Black fumes, more ominous than any thunderhead, eased upward over the backstretch.
- That happened when the cloud of suspicion about doping that generally hovers over cycling turned into a veritable thunderhead, and started raining allegations down upon some of the .
- Within 15 minutes of my first fireball sighting, thunderhead clouds that had been threatening ominously suddenly bore down with full force.