1415 battle (9)
I believe the answer is:
agincourt
'1415 battle' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for agincourt that I've seen before include "Battle in Hundred Years' War" , "Battleground" , "October twenty four, 1415 battle" , "Fourteen fifteen English victory" , "1415 battle in the Pas-de-Calais" .)