A streak is an unbroken series of the same result happening again and again. When a basketball team wins ten games in a row, they're on a winning streak. When it doesn't rain for thirty days straight, that's a dry streak. The key idea is continuity: the moment the pattern breaks (the team loses, or rain finally falls), the streak ends.

Streaks can be good or bad. A student might be on a streak of perfect spelling tests, feeling more confident each week. A baseball player in a hitting streak gets at least one hit in every game, sometimes for dozens of games running. But you can also be on a losing streak or have a streak of bad luck.

The word has another meaning too: a thin line or mark of a different color. You might see streaks of lightning across a stormy sky, or notice streaks of gray in your grandfather's dark hair. Paint that isn't mixed well might dry with visible streaks in it.

When something streaks across the sky, it moves very fast and may leave a bright trail behind it, like a meteor streaking across the night sky. When someone streaks ahead in a race, they surge forward suddenly and powerfully. The image is of something moving so fast it becomes a blur.