Revenue is sales but can include other income like fees or interest. It’s an all-inclusive number of how much money a company brings in as a result of all of its activities. If company XYZ sells $10 million worth of lollipops and earns $1 million in interest from all that cash, then its revenue will be $11 million.

The service sector is perhaps best defined as what it’s not: manufacturing, construction, or agriculture. Almost every other industry – from accounting to law, restaurants, and leisure activities – is part of the service sector. In big, developed economies, it tends to make up the bulk of economic activity (e.g. it’s about 80% of the economy in the US).

A short is when an investment is set up such that it will profit if the price of something goes down. For example, you can “short” the oil price – effectively, you’re betting that it’ll go down. Shorting can be very profitable (anybody who shorted the oil price in 2014 would have made a lot of money) but is also very risky (because you can lose more than what you invested).

A stock is a financial product that indicates ownership of part of a business, typically with a claim on part of the profits and assets of that business. The stock of public companies is traded on stock exchanges.

A stock exchange is, quite literally, a facility where stocks are exchanged – i.e. traded. Examples include the New York Stock Exchange and the Hong Kong Stock Exchange.

A VC fund is a type of investor that typically invests in private, early-stage companies. Usually, VC firms invest in companies that they think will grow very quickly in the near future due to, for example, innovative technology the company’s developing.

Volatility is a statistic that measures the differences between returns of an investment over a given time period – a greater difference means greater volatility. Generally, the higher the volatility, the more risky an investment is considered to be.