*Torrential* describes rain that falls extremely hard — not a shower, not merely heavy, but water coming down in sheets, so fast that drains cannot swallow it and streets begin to flood. Taiwanese students have the perfect picture already: the rain of a typhoon afternoon, or a summer 午後雷陣雨 at its worst. That is torrential rain.

In practice the word is nearly welded to one noun. *Torrential rain*, *torrential downpour*, *torrential rainfall* — those three cover almost every real use, and weather reports lean on the phrase constantly. If you use it about anything else, it will sound odd, with two exceptions worth knowing: writers sometimes speak of torrential floods or a torrential river (water rushing violently), and, more rarely and always as a deliberate image, of a torrential flow of words from someone who will not stop talking.

A point about strength: this is already a strong word, so "very torrential" sounds wrong to a native ear, a bit like saying "very enormous". The word has the *very* built in.

It is neutral in register — the newspaper says it, the weather forecaster says it, and an ordinary person telling you why they arrived soaked says it too. It is not a bookish word like *torpid*. What it is not, though, is a word for long rain. Rain can be torrential for twenty minutes; the word is about violence and volume, not duration. For rain that simply will not stop for three days, English says *persistent rain*, or that it *rained non-stop*.