storm cloud 
noun
1A heavy, dark rain cloud: black storm clouds rolled inexorably down the valley...
- They shoot up from the tops of thunderstorms about the same moment lightning discharges within the storm cloud.
- Instead of the uniform grayness of the rainy day, we have the black storm cloud and brilliant lightning flash.
- When the local topography permits, you can see lightning and the associated storm cloud from anywhere up to 200 miles away.
1.1 (storm clouds) Used in reference to a threatening or ominous state of affairs: the beginning of the decade saw storm clouds gathering over Europe...
- Some perceive the storm clouds gathering over Egypt's political life.
- Collins had seen the storm clouds gathering over East Timor's future.
- Zweig saw the storm clouds gathering over his native Austria earlier than many.
- platen
- plate nail
- platen knob
- platen machine
- platen press
- platen printing machine
- platen roller
- plate number
- plateosaur
- Plateosaurus
- plate painter
- plate paper
- plate pie
- plate powder
- plate printer
- plater
- plate rack
- plate rail
- plate railway
- plateresque
- Plate, River
- plate roll
- plate room
- plate shears
- plate ship