An absurd notion

How do you classify a person as a gamer? Is it simply someone who plays games? We live in the age of information, and almost everybody in first- and second-world countries has a device that can play a game. So by this definition, everybody and their grandmothers (literally) would be considered a “gamer.” And that would be an absurd notion.

Then what constitutes a gamer? Is it someone who plays over a certain amount of time in a week? But no, that would mean that children are gamers, too. Is it somebody who is willing to spend money on gaming peripherals / gear? Well, no, now it just seems like a title that can be bought.

So what makes a person a gamer?