A company is just a business that people own. When a business needs money to grow — to hire people, build products, open shops — one way to raise it is to sell small slices of ownership to the public. Those slices are called shares (or "stock").

If a company is divided into a million shares and you own one, you own one-millionth of that business. That entitles you to a share of its future profits (sometimes paid out as a dividend) and a vote on big decisions. If the business becomes more valuable, your slice becomes more valuable too — and if it struggles, your slice is worth less.

At first, a company's shares are usually held privately by its founders and early investors. When it decides to sell shares to the general public for the first time, that event is called an Initial Public Offering, or IPO — people say the company is "going public" or "listing".

After the IPO, the shares trade on a stock exchange, where anyone can buy them from or sell them to other investors. The company got its cash at the IPO; from then on, the day-to-day price is just people buying and selling those existing shares among themselves.

This is a key idea: when you buy Apple shares, you're not usually buying them from Apple — you're buying them from another investor who wants to sell.

A stock exchange is the organised marketplace where shares are bought and sold. The big ones you'll hear about are the London Stock Exchange (LSE), the New York Stock Exchange (NYSE) and the Nasdaq. Each lists thousands of companies.

Exchanges are only open during set hours. For example, the main US market runs roughly 9:30am to 4:00pm New York time, Monday to Friday; London runs 8:00am to 4:30pm UK time. Outside those hours the market is closed, though some products (like currencies and futures) trade nearly around the clock across global sessions.

Lots of different players trade at once, and it helps to know who they are:

• Retail traders — everyday individuals like you, trading their own money through an app or broker.
• Institutions — banks, pension funds and hedge funds moving very large sums.
• Brokers — the companies that give you access to the market and place your orders (for example, a trading app).
• Market makers — firms that always stand ready to buy and sell, which keeps the market "liquid" so your order can fill quickly.

A share doesn't have an official price handed down by anyone. The price is simply the last amount someone was willing to pay, and someone else was willing to accept. It moves constantly as buyers and sellers change their minds.

At any moment there's a highest price buyers will pay (the bid) and a lowest price sellers will accept (the ask). When a buyer and seller agree, a trade happens and that becomes the new price. More eager buyers than sellers push the price up; more eager sellers push it down. That's supply and demand in action.

A ticker is the short code for a company — AAPL for Apple, TSLA for Tesla — usually shown next to its current price and how much it's changed today.

A price chart plots the price over time: time along the bottom, price up the side. Zoom out and you see the long-term trend; zoom in and you see today's wiggles. Most traders use "candlestick" charts, where each candle shows the open, high, low and close for a slice of time — but at this stage, just knowing that up-and-to-the-right means rising, down means falling is enough.

Shares are just one of several markets you can trade. In plain terms:

• Stocks (equities) — slices of individual companies.
• Indices — a basket that tracks many companies at once (e.g. the S&P 500, the FTSE 100).
• Forex (FX) — currencies traded in pairs, like GBP/USD; the largest market in the world and open 24/5.
• Futures — contracts to buy or sell something (an index, oil, gold) at a set date; popular with active traders and most prop firms.
• Crypto — digital assets like Bitcoin; trades 24/7 and is highly volatile.