conglomerate
A huge company that owns many different kinds of businesses.
A conglomerate is a large corporation made up of several different companies that often do completely unrelated things. Imagine one giant company that owns a movie studio, a hotel chain, a candy factory, and an insurance company all at once. That's a conglomerate.
For example, a conglomerate might own both a television network and a cruise line. These businesses have nothing to do with each other, but they're both owned by the same parent company. The leaders of a conglomerate believe that owning many different types of businesses protects them if one industry struggles. If people stop watching as much TV, the cruise ships might still make money.
You'll often see conglomerates in news stories about major corporations. When a huge company buys another company in a totally different industry, it's usually building a conglomerate. Some famous conglomerates own hundreds of smaller companies, and you might use their products every day without realizing they're connected.
In geology, conglomerate also refers to a type of sedimentary rock made of rounded pebbles naturally cemented together.