trilateral

Imagine a triangle: it has three sides, right? That is where "trilateral" begins. At its simplest, it means having three sides. More often, though, it is used for agreements, talks, or relationships between three groups or countries. Think of a summit between the U.S., Canada, and Mexico. That is a clear example of something "trilateral" in action. You probably will not use it for everyday objects, but you may hear it often in news stories about diplomacy and international talks.

The word "trilateral" combines the prefix "tri-," meaning three, with "lateral," which relates to sides. In the most basic sense, it describes something with three sides. But in modern English, it is used much more often to describe a situation that involves three parties or three countries working together.

You will see this most often in international relations and diplomacy. A "trilateral agreement" is an agreement among three countries, such as the United States-Mexico-Canada Agreement (USMCA). These agreements may deal with trade, security, or any other area where three-way cooperation matters. You might also hear about a "trilateral commission," which is a group with representatives from three countries meeting to discuss shared concerns.

Less often, "trilateral" can also appear in technical writing to describe something with three sides or three connected parts. So even though you may not use it every day, it is a useful word when the idea of "three working together" is exactly what you want to express, especially in politics, diplomacy, and formal discussion.