Other forms: thunderheads
A thunderhead is the towering cloud that comes before a storm. A thunderhead building, thunderheads on the horizon, watch the thunderhead.
It is the anvil-topped cloud that can stand fifteen kilometres high, and the flat top is where it hits the stratosphere and spreads sideways because it can rise no further. Seeing one grow is the clearest warning of a storm there is.
1nounthunderheadThe towering cloud that comes before a storm.
“A huge thunderhead was building over the mountains, so we hurried back to the hut.”
thunderhead is a cloud.
Thunder plus head, an American formation of the nineteenth century.
From thunder + head.
Etymology from Wiktionary, CC BY-SA