ECN Broker
Electronic Communication Network - your order hits the interbank market directly. Tight spreads + commission.
ECN matches your order against other traders and banks directly. Near-zero spreads; commission ~$3-7 per lot round trip. Better for active traders. Most 'ECN' in retail is technically STP, but execution is usually still solid.
Learn to actually use ECN Broker.
Definitions are the easy part. The free first five modules put this on a real chart and make you do the work. No card required.