A cold call is calling a bet AND a raise on a street where you have not put any money in the pot.

Pre-flop, since the blinds count as bets, all it takes is someone to raise (not limp) pre-flop and players behind the opener can cold call... unless they're in the blinds, who have already bet this round.

So, when you're in the blinds, you can not cold call - by definition.

Of course, once one person calls, anyone can over call.