Tangential means barely connected to the main point or topic, like a side comment that wanders away from what really matters. The word comes from tangent, a mathematical term for a line that touches a circle at just one point before heading off in its own direction.

When your friend starts telling a story about soccer practice but somehow ends up talking about what she had for breakfast, that breakfast detail is tangential: it touched the main story but wasn't really part of it. During class discussions, a student might make a tangential remark that's loosely related to the lesson but takes everyone off track.

Something tangential isn't completely random or unrelated. It has some connection, however slight, to the main subject. If your class is discussing the American Revolution and someone mentions the French Revolution, that's tangential: there's a connection, but it's not central to what you're studying. A tangential relationship between two things means they're connected, but only barely.

Teachers sometimes need to recognize when discussions become too tangential and guide everyone back to the main topic. In your own writing, you can look for tangential sentences that don't strengthen your main argument. They might be interesting, but if they lead readers away from your point, they probably don't belong in your final draft.