Battlecruisers as a spectrum of roles

The opening argument separates ships meant chiefly to fight the enemy battle fleet from cruisers intended to control trade routes and defeat lesser warships. Battlecruisers could sit anywhere between those poles, so role, endurance, speed, protection, and internal structure matter more than a label alone. This framework explains why ships with superficially similar guns or speeds could be classified differently by their navies. Early Invincible-type commerce-raider hunters and Lion-type ships tied more closely to fleet reconnaissance occupy different points on the spectrum.