Slippage occurs in trading when the desired price of an order is not achieved due to rapid market fluctuations or delays in order execution. It can result in a trade being executed at a price different from the one expected. Slippage can occur in both directions, causing you to either gain or lose more than anticipated.

Slippage is common during periods of high market volatility or low liquidity, such as major news releases or market opening times.

Spread serves as a vital metric in the forex market, illustrating the disparity between the buying and selling prices for a currency pair. It is expressed in pips, which represent the smallest price movement that an exchange rate can make based on market convention.

For instance, if the EUR/USD currency pair has a bid price of 1.1500 and an ask price of 1.1502, the spread would be 2 pips. This means traders need the currency pair's value to appreciate by at least 2 pips before they can begin to realize a profit due to this cost.

Understanding the spread is crucial for traders, as it directly impacts profitability. A narrower spread can be advantageous as it reduces the breakeven level for trades, while wider spreads can increase costs and potentially diminish profits. Therefore, monitoring and considering the spread, along with other factors, is essential for devising effective trading strategies and optimizing outcomes in the forex market.

The relationship between rollover and spreads is interlinked. During periods of high market volatility or low liquidity, spreads tend to widen, reflecting the market's perception of increased risk and uncertainty. When spreads widen, the cost of executing a trade can also increase.