Bid & Ask

Bid and ask are the two simultaneous prices that make up a market quote: the bid is the highest price buyers in the market are currently willing to pay (so it is where you, as a seller, can sell), and the ask or offer is the lowest price sellers will accept (so it is where you, as a buyer, can buy). The ask sits above the bid, and their difference is the spread — the immediate cost of crossing the market. Because you transact at the side that works against you, your entry begins underwater by roughly the spread until price moves your way. Bid and ask both move continuously with supply and demand, and the spread between them widens when liquidity is thin or volatility is high. Reading both prices, not just a single "price", is fundamental to understanding execution and cost.

In plain English — Every instrument is quoted with two prices at once. The bid is the price at which you can sell, and the ask (sometimes called the offer) is the price at which you can buy. The ask is always slightly higher than the bid, and the gap between them is the spread. You always trade at the less favourable of the two — buying at the higher ask, selling at the lower bid — which is why a fresh position starts a little behind.

EUR/USD is quoted 1.1000 / 1.1002. You buy at the ask (1.1002) and sell at the bid (1.1000), so the 2-pip difference is the spread you pay to get in and out.