Wherein Hooded breaks out a few modded gaming terms and examines them, and fires the dog-zooka as a last resort.
 
Pet is generally considered a term of affection. While many people, arguably justifiably, are trying to recast the role of "the family pet" to a family companion, where the human beings are considered the animal's guardian and not so much an owner, it's generally understood that if you have a pet you watch out for it, provide for it, and treat it humanely. Others will say the term owner has a secondary meaning in this case, and is closer to "guardian" than this contentious re-imagining would suggest. Pet as a term can even be used on humans, with the affection usually in place, although it at times can explicitly imply ownership or dominance (I won't get into it; if you want to learn more, the internet is waiting for curious little innocents to wander into its deep, dark forest). The argument against using the term pet often points toward this parallel meaning, where those who call another pet are establishing a hierarchy, and that the "pet" is somehow lesser. This is fine for some people, but others, even though they still use the term pet to describe the animal that lives with them, will still treat this creature as a full member of the family.
 
In gaming, usually in online RPGs, the source of alternate languages the likes of which only crazy cults can rival, "pet" tends to mean something very specific, a semi-NPC companion that travels with or is summoned by the player character, used to supplement the player's arsenal of abilities and, most importantly, act as a secondary tank of sorts, to distract attackers so the main character can pummel them from a distance. Here the hierarchy is obvious: the pet's well-being is sacrificed for the sake of its owner.
 
Contrasted with real life, you would rarely meet anyone who would use a "pet" in such a fashion. Focusing on dogs, some cultures and families can't get past the idea of dogs being little more than trainable guardians, sort of a meat shield for the home, but I like to think that this is usually thought of in a defensive sense. Still, as I began writing this I realized that yes, real life does have examples of animals, most often dogs, being used in ways similar to the way pets are used in MMOs. What's crucial, though, is that the terminology tends to change when they're employed in this way. The term pet gets taken out and replaced with guard dog, police dog, bomb-sniffing dog. If they're at any time a pet, it seems this term would be used when the dog is not at "work", when it's at the home of its caretaker, being treated as a member of a family or at least being given decent food and a place to sleep.
 
I think in games the term pet is a bit tongue-in-cheek, and may stem from the way MMOs are played. You often show off, even if unintentionally, with your character, so the term pet may be applied just as often when you're showing off the creature to your friends to show what level of ability you've reached. Even affection could be applied, because you know that, unlike in real life, the creature you call a pet won't get mangled or die as a result of combat (even if the pet is a robot, golem, spirit, or shambling undead). At worst you'll need to re-summon it, and it'll be just as dutiful and bright-eyed as the day you first got it. Fallout, Dragon Age, and Fable try to add a bit more consequence to the pets they introduce, but in so doing, I feel, they sort of move out of the feel of the term "pet" and approach companion, because the animals aren't just a source of empathy, however forced, but they're also able characters that love biting genitals for justice. Pet, again, seems only to apply when they're not doing their jobs as combatants or treasure finders.
 
(Don't get me started on how Rinoa treated her pet, though.)
 
No matter how much one protects a real life pet from harm, it will eventually die. In some games, like with main characters, there is an implicit immortality. So, while the virtually brutal treatment of an animal in a game suggests one doesn't care about its welfare, when the rules are such that you can get that animal back without consequences, suddenly the two definitions of pet don't seem so far apart.