A billion is a large number that is equivalent to 1,000 million or 1,000,000,000. In other words, a billion is written as 1 followed by 9 zeros, or 1,000,000,000 in numerical form. To put this in perspective, one billion seconds is equal to approximately 31.71 years, and one billion dollars is enough to make someone a billionaire and can buy a private island or a professional sports team.

In different countries, the meaning of “billion” can vary. In some countries like the United Kingdom, a billion traditionally referred to a number equal to 1,000 million millions, or 1,000,000,000,000. However, in the United States and many other countries, a billion commonly refers to a number equal to 1,000 million.