Commission
Commission is a per-lot flat fee a broker charges in addition to (or instead of) the spread on Raw and ECN accounts.
Commission is the broker's explicit charge per round-turn trade, typically expressed as a dollar amount per standard lot (100,000 units). Raw / ECN accounts quote near-zero spreads (0.0–0.3 pips) but add a commission, usually $3–$7 per side per standard lot — so $6–$14 per round turn. Standard accounts bundle the commission into a wider spread (1.0–1.8 pips on EUR/USD) and quote 'commission-free'. The total cost-to-trade matters, not the structure: for a 1-pip move on EUR/USD ($10), a $3.5 commission per side + 0.1 pip spread = $8 total, cheaper than a 1.5-pip Standard spread that costs $15. Active traders almost always come out ahead on Raw/ECN once volume crosses ~10 lots/month.
Worked example
Exness Raw Spread account on EUR/USD quotes 0.0 pip spread + $3.5 commission per side per lot. A 1-lot round turn costs $7 in commission, regardless of how far the trade runs. The same 1-lot trade on Exness Standard costs roughly $13 (1.3-pip spread, no commission) — Raw saves $6 per lot.