TEAM is another way to say "Everybody but me." It's popular in corporate environments where an asshole wants work done, but doesn't want to do it, but wants to seem like they want to. Therefore they start their email with "TEAM"

I couldn’t care less (but one must keep up appearances, right?)

to be part of another group of people, working togeter

the people you always roll with basically your crew or click

Together Everyone Acheives More

a common term used in online video games when one team has a numerical advantage of atleast two extra playersover the other

when "teams" is called out, players should view the number of players for each team and make them even by switching or spectating

however, if a team has only a one man advantage eg, 8v7....it is not appropriate to call out teams

Being a team means being committed to something and sticking to it. It means even when you feel sick, depressed, or you have plans, you still participate and stay committed. No skipping. No 'Wahh, I don't fell good." No "I'd rather hang out with my boyfriend." All in all, TEAM means staying committed, showing up even when you don't want to, and giving all you've got. If you aren't willing to do that, they don't bother being part of a team.