A toss is when something is thrown lightly in the air like this.

So, Jonathan, who do you think's going to win the big football game tomorrow?

Oh, I don't know.

It's a toss up.

Really.

Orlando has a great offense, but Baltimore has a great defense.

Either team could win.

Wow, you seem to actually know something about these teams.

Well, who do you think will win?

I'm just going to cheer for whoever is wearing the best colors.

So Orlando.

We used the expression toss up to describe a situation where the result is unclear and could go either way.

It refers to the actual tossing off a coin and making a decision based on that, and that's English in a minute.