epigraph

Concise Oxford English Dictionary © 2008 Oxford University Press:
epigraph /ˈɛpɪgrɑːf/

▶noun

• 1 an inscription on a building, statue, or coin.

• 2 a short quotation or saying at the beginning of a book or chapter, intended to suggest its theme.

– origin C16: from Gk epigraphē, from epigraphein ‘write on’.