This is the 17609th most frequent Russian word.
туч
"Туч" is the genitive plural form of "туча," meaning "cloud."
The word "туча" in this sentence refers to a storm cloud, highlighting its presence in the sky as part of weather phenomena.
Туча грозовая медленно плывёт по небу.
The storm cloud slowly drifts across the sky.
Here, "туч" is in its plural form, emphasizing multiple storm clouds seen at a distance.
На горизонте виднелось множество туч, предвещая дождь.
On the horizon, numerous clouds were visible, foretelling rain.
The term "тучи" refers to storm clouds in general, creating a visual image of their collective impact on the scene.