One single crash of thunder — not the long rumbling that rolls on and on, but the one sharp bang, the kind that makes you jump. A thunderclap is countable: you can hear one thunderclap, or three. That is the useful thing about the word, because 'thunder' itself is uncountable (you cannot say 'a thunder'), so when you need to count them, this is the word English gives you.

One single crash of thunder指一聲雷響 — not the long rumbling that rolls on and on不是那種一直轟隆轟隆滾下去的長雷聲, but the one sharp bang而是那一聲清脆的巨響, the kind that makes you jump會讓你嚇一跳的那種。A thunderclap is countablethunderclap 是可數名詞: you can hear one thunderclap, or three你可以聽到 one thunderclap，或是 three。That is the useful thing about the word這就是這個字好用的地方, because 'thunder' itself is uncountable因為 thunder 本身是不可數的 (you cannot say 'a thunder')（不能說「a thunder」）, so when you need to count them所以當你需要數雷聲的次數時, this is the word English gives you英文就給你這個字。

It sounds slightly literary — in ordinary talk people are more likely to say 'a clap of thunder' or just 'that was loud!' — so you will meet it most in stories and news writing.

It它 sounds slightly literary聽起來有點文學味 — in ordinary talk日常說話 people are more likely to say 'a clap of thunder'比較會說「a clap of thunder」 or just 'that was loud!'或直接說「that was loud!」 — so you will meet it most in stories and news writing所以你最常在故事和新聞寫作裡遇到它。

Writers also use it for something that is not weather at all: news that arrives suddenly and shocks everyone. 'The announcement came like a thunderclap.' In that use it means the shock, the suddenness, not the noise.

Writers作家 also use it for something that is not weather at all也會用它來形容跟天氣完全無關的事: news that arrives suddenly and shocks everyone那種突然傳來、讓大家都嚇一跳的消息。'The announcement came like a thunderclap.'「The announcement came like a thunderclap.」 In that use it means the shock, the suddenness這種用法指的是那種震驚感、那種突然, not the noise不是聲音本身。