(n.) A cloud charged with electricity, and producing lightning and thunder.

Cloudcuckooland alto-cumulus alto-stratus angry clouds anvil cloud banner cloud billowy cloud black cat black clouds broken mirror cap cloud cirro-cumulus cirro-fillum cirro-nebula cirro-stratus cirro-velum cirrus cirrus cloud cirrus haze cirrus stripe cloud cloud band cloud bank cloud drift cloud mass cloud street cloudland cloudling cloudscape cocktail cottony cloud cumulo-cirro-stratus cumulo-cirrus cumulo-nimbus cumulo-stratus cumulus cumulus cloud curl cloud danger sign early symptom falling barometer fleecy cloud fractocumulus gathering clouds halcyon bird high fog high sign mackerel sky mammatocumulus mushroom cloud nimbus nimbus cloud omen owl precursor preliminary sign premonitory sign premonitory symptom prodroma prodrome quarantine flag rain cloud rainbow raven red flag red light scud shooting star skull and crossbones snail cloud squall cloud storm cloud storm clouds storm petrel stormy petrel strato-cumulus stratus stratus cloud symptom thunderhead warning sign warning signal water carrier woolpack yellow flag yellow jack