fossil

n. the remains of a plant or animal that have turned into stone over millions of years.

n. the mineralised remains or traces of an organism from a past geological age.

“The children found a small fossil of a shell while walking along the beach.”

“The discovery of a well-preserved dinosaur fossil in the desert provided researchers with new insights into the species' social behaviour.”

n. an unkind way to describe a person who is very old or has very old-fashioned ideas.

n. a derogatory figurative term for an elderly person or someone perceived as being hopelessly behind the times.

“My boss is such a fossil; he still wants us to send everything by fax.”

“The younger engineers viewed the department head as a fossil who refused to adopt modern software solutions.”

Informal · Humorous

n. a word that is only used in one specific phrase and is not used anywhere else in modern English.

n. a word preserved in a specific idiom or frozen phrase while having otherwise fallen out of general use.

“The word 'fro' in the phrase 'to and fro' is a fossil because we don't use it alone anymore.”

“Linguists often study fossil words like 'kith' to understand the historical development of English collocations.”

Technical

adj. relating to or being a fossil.

adj. pertaining to, of the nature of, or converted into a fossil.

“The museum has a large collection of fossil bones from the Jurassic period.”

“The environmental impact report focused on the preservation of fossil tracks discovered during the initial excavation of the site.”