to leave a mark on something that is difficult to remove

Tomato sauce stains terribly - it's really difficult to get it out of clothes. 让番茄酱沾上很麻烦——很难把它从衣服上洗掉。

While she was changing the wheel on her car, her coat had become stained with oil. 她给汽车换轮胎时，外套沾上了油污。

If a material stains, it absorbs substances easily, causing it to become covered with marks, or coloured by a chemical.

This carpet is ideal for the kitchen because it doesn't stain easily. 这块地毯很适合在厨房里用，因为它很耐脏。

to change the colour of something using a chemical

She stripped the floorboards and stained them dark brown. 她刮掉原来的漆，把地板刷成了深棕色。

to permanently spoil something such as someone's reputation

Several important politicians have had their reputations stained by this scandal. 好几位重要的政界人士都因为这起丑闻而名声受损。

The country's history is stained with the blood of (= the country is guilty of killing) millions of innocent men and women. 这个国家的历史沾满了数百万无辜者的鲜血。

a dirty mark on something that is difficult to remove

a blood/grass stain 血污／草渍

You can remove a red wine stain from a carpet by sprinkling salt over it. 地毯上红酒的污渍可以通过撒些盐来清除。

a chemical for changing the colour of something

permanent damage to someone's reputation or character

His solicitor said, "He leaves this court without a stain on his character." 他的律师说：“他走出法庭时名声将丝毫无损。”