Why is the deus ex series reffered to as deus ex

Deus ex is Latin. Loosely translated it means "Like god". Deus ex is all about human augmentations and cyborganics that are all controlled by huge corporations. Each augmentation is directly connected to a central system for each company so that they can monitor the augmentations and your state of health (they can even take remote control of them if necessary). There is also Neuropozyne, the anti-rejectant drug that people with augments will normally need to take to stay alive.

Combine both of these elements, and appears as though the companies can both can control augmented people's bodies, minds (if they have neural augmentations) and even their wallets and lives (neuropozyne). Human purists argue that this is completely unfair, and that companies have gone to the extreme to gain power and wealth. The companies have become so powerful, they nearly overtake government.

In short, the companies effectively rule over the people that have their augments, making them "Like god" to all of their customers.