[ 'fɒs(ə)l , -sɪl ]
■ noun
1》 the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form.
2》 humorous an antiquated person or thing.
3》 a word or phrase that has become obsolete except in set phrases or forms, e.g. hue in hue and cry .
Origin
C16: from Fr. ~e , from L. ~is 'dug up'.