The story
Blend of battleship + cruiser, from being a cruiser-like ship with battleship-like capabilities and possibly operating in the battleline.
Etymology from Wiktionary, CC BY-SA 4.0.
battlecruiser
Today it means: A fast warship with thicker armor and heavier guns than a typical cruiser, but with armor, armament, or both still inferior to that of a dreadnought battleship; designed to act as an advanced scout of the battle fleet and to destroy enemy cruisers. Full definition →