Cartridge
A complete round of ammunition: case, primer, powder, and bullet assembled together. Named after the case, not the bullet it is loaded with.
Not to be confused with “bullet” (just the projectile) or “shell” (a shotgun term). A 6.5 Creedmoor cartridge is the whole assembly, ready to chamber.
Cartridges are named after the case, not the bullet. The .308 Winchester refers to the case design, which can be loaded with bullets from roughly 110 to 220 grains.