fossil
/ˈfɒsəl/noun
1- the remains or impression of a prehistoric plant or animal preserved in petrified form or as a mould or cast in rock化石。
1.1
- derogatory or humorous an antiquated or stubbornly unchanging person or thing〈贬或幽默〉陈年往事; 僵化（或守旧）的人; 顽固不化者：
he can be a cantankerous old fossil at times.
他有时会是个难对付的老顽固。
1.2
- a word or phrase that has become obsolete except in set phrases or forms, e.g. hue in hue and cry习语中保持的旧词（或短语）（如 hue and cry中的hue）。
词源
mid 16th cent. （denoting a fossilized fish found, and believed to have lived, underground）： from French fossile, from Latin fossilis 'dug up', from fodere 'dig'.