To make food or a drink hot again after it has gone cold — last night's rice, cold coffee, the soup you made on Sunday. In practice this almost always means the microwave, though a pan or an oven counts too.

To make food or a drink hot again把食物或飲料reheat（重新加熱） after it has gone cold在它冷掉之後 last night's rice像昨晚的飯 cold coffee冷掉的咖啡 the soup you made on Sunday你星期天煮的湯 In practice實際上 this almost always means the microwave這幾乎都是指用微波爐 though a pan or an oven counts too不過用平底鍋或烤箱也算

It is a plain, useful word, but here is the honest part: in daily conversation people usually say 'heat it up' or 'warm it up' rather than 'reheat it'. Reheat sounds slightly more formal or technical, and it turns up most on packaging and in recipes — 'reheat thoroughly before serving', 'do not reheat once cooled'. Both are correct; just know that if you say 'I'll reheat the soup' to a friend, you sound a shade more careful than they would.

It is a plain, useful word這是個平常好用的字 but here is the honest part不過老實說 in daily conversation在日常對話裡 people usually say 'heat it up' or 'warm it up'人們通常會說「heat it up」或「warm it up」 rather than 'reheat it'而不是「reheat it」 Reheat sounds slightly more formal or technicalreheat聽起來稍微正式或技術性一點 and it turns up most on packaging and in recipes而且最常出現在包裝和食譜上 'reheat thoroughly before serving', 'do not reheat once cooled'像是「reheat thoroughly before serving」、「do not reheat once cooled」 Both are correct兩種說法都對 just know that知道就好 if you say 'I'll reheat the soup' to a friend如果你對朋友說「I'll reheat the soup」 you sound a shade more careful than they would你聽起來會比他們平常講的稍微講究一點

There is also a noun form, but it is rare and specialised — engineers use 'reheat' for a stage in a steam or jet engine where a fluid is heated a second time. You are unlikely to need it.

There is also a noun form也有名詞用法 but it is rare and specialised不過很少見也很專門 engineers use 'reheat'工程師會用「reheat」 for a stage in a steam or jet engine指蒸汽機或噴射引擎裡的一個階段 where a fluid is heated a second time在這階段流體會被二次加熱 You are unlikely to need it你大概用不到這個

Stress falls on the second part: re-HEAT.

Stress falls on the second part重音在後面 re-HEATre-HEAT