/
ˈfɒs(ə)l, 
-sɪl/
n.
   - the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form.
 - humorous an antiquated person or thing.
 - a word or phrase that has become obsolete except in set phrases or forms, e.g. hue in hue and cry.
 
Etymology
C16: from Fr. fossile, from L. fossilis ‘dug up’.