epigraph
noun /ˈepɪɡrɑːf/
  /ˈepɪɡræf/
 - a line of writing, short phrase, etc. on a building or statue, or as an introduction to part of a book- The epigraph to the chapter read: ‘One man’s freedom is another man’s slavery’.
 Word Originlate 16th cent. (denoting the heading of a document or letter): from Greek epigraphē, from epigraphein ‘write on’.