Discrete - it was manufactured separately, and sold separately as different product. Note: laptop manufacturers buy them from different vendors, but when they assemble it, it becomes one piece of the machine. Afaik, you can only upgrade laptop DVD drive/hard drive/RAM.
Also discrete graphics cards have their own memory, and not stealing them from system RAM, like onboard solutions do.
ok! and what is name we give for laptop's upgradeables graphic cards?