What do you mean by ECN account with low spreads?

Hi everyone, I don’t understand clearly that What is the ECN account with low spreads? Someone tell me by given details about ECN account with low spreads. Please help me.

How much are you planning to invest? Low spreads but you pay commission per traded lot. If you plan to invest small money go for STP rather than ECN. If you are planning to scalp and/or trade on economic news then ECN is for you despite the high costs