1. Something which, or someone who, survives or remains after the loss of
others (compare relic).
2. (archaic) The surviving member of a married couple; a widow or widower.
3. (biology, ecology) A species, organism or ecosystem which was once
widespread but which is now found only in a few areas: some think the
Loch Ness monster is a relict from the age of dinosaurs.
4. (geology) A structure or other feature which has survived from a
previous age: dark rims are a relict of a primary interaction between
basalt and seawater.
5. (linguistics) A word or language which survives as an archaicism.