One reason is that printing is not quite the right word for some of the technologies given this label. Whereas hobbyist-scale 3D printers typically build a product by squirting out blobs of plastic, a technique called selective laser melting zaps successive layers of powder with a laser or ion beam, hardening only certain bits.
Another reason for being picky about terminology is that big companies want to stress the “manufacturing” aspect: the technology has moved beyond the development labs and is now being used on the factory floor to make complex metal parts.
