To proliferate means to grow or spread rapidly in number. When something proliferates, it multiplies quickly, like dandelions spreading across a lawn or rumors spreading through a school hallway.

Scientists use this word to describe cells dividing and multiplying, especially when studying growth and disease. In the 1800s, factories proliferated across industrial cities as manufacturing spread. Today, smartphones have proliferated around the world: something that barely existed twenty years ago now appears everywhere.

The word carries a sense of abundance and speed. One or two of something might appear, then suddenly there are dozens or hundreds. Social media posts can proliferate in hours, reaching millions of people. Information, ideas, and technologies can all proliferate when conditions allow them to spread easily.

Notice that proliferate doesn't make a judgment about whether the growth is good or bad. Helpful innovations proliferate, but so do problems like plastic waste or invasive species. The word simply describes rapid multiplication and spread, whether we welcome it or not.