Spread
Also known as: Bid-Ask Spread
The spread is the broker's primary cost component on a trade — the gap between the price you buy at (ask) and the price you sell at (bid), measured in pips. A 1.2-pip spread on a EURUSD quote of 1.08500 / 1.08512 means you start the trade 1.2 pips down before any market move.
Spreads come in two flavors: fixed (constant regardless of market conditions) and variable (widening during volatile sessions or news). ECN/Raw accounts typically charge tighter raw spreads plus a per-lot commission; standard accounts mark up the spread and skip commissions.