When does the Galaxy class become a battleship?

Should the Galaxy-class Enterprise be considered a battleship because of its size and wartime firepower?

Normally it is a cruiser, but stripping out its exploration facilities for a pure warfighting fit could make it a battlecruiser or battleship.

The normal Galaxy class is a cruiser by mission despite its bulk. Its laboratories, civilian accommodation, and other exploratory spaces consume much of the large hull. Removing those functions and devoting the freed volume to fighting systems changes the ship's role as well as its combat power. That wartime configuration could reasonably be called a battlecruiser or battleship.