In 'bread knife', the word 'bread' is used adjectivally.

在词组bread knife中，bread用作形容词。

《牛津词典》

Then, he cut his finger with the bread knife.

然后，他用面包刀伤了他的手指。

youdao

"I have a bread knife, you know," she said. "Somewhere."

你知道，我有把面包刀，放在某个地方。

youdao

The serrated bread knife cuts with a sawing motion instead of a downward force, keeping your sandwich from getting smooshed.

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Mr Golding, who had become father a fortnight before the tragedy, was stabbed with a bread knife when he caught the heroin addict burgling his home in Erdington, Birmingham.

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