To encounter means to meet or come across something or someone, often unexpectedly. When you encounter a deer while hiking in the woods, you didn't plan to see it, but suddenly there it is on the trail ahead. When you encounter a difficult math problem on your homework, you've run into something challenging you need to deal with.

The word often suggests an element of chance or surprise. You might encounter an old friend at the grocery store, or encounter a new word while reading a book. Explorers encounter unknown lands and creatures. Scientists encounter puzzling results in their experiments that lead to new discoveries.

An encounter can also be used as a noun to describe the meeting itself. A friendly encounter with your neighbor might brighten your day, while an encounter with a grumpy teacher in the hallway might make you nervous. Some encounters are brief, like passing someone on the street, while others are more significant, like Lewis and Clark's encounters with Native American tribes during their expedition.

The word carries a sense of something coming into your path rather than you seeking it out, though you still have to respond to what you encounter.