/striːk/
[noun] A long, thin line or mark that is different in colour or texture from the surface around it; also used to describe a continuous run of something, such as good luck or success.
The word 'streak' once meant simply a line drawn by a finger — the idea of a 'winning streak' came nearly a thousand years later.
The word 'streak' reaches back to the very earliest layers of English, descending from the Old English word 'strica', meaning a stroke, a mark, or a line. This Old English form came from the Proto-Germanic root *strikan-, which carried the sense of stroking, rubbing, or drawing something across a surface. That same ancient root gave rise to closely related words across the Germanic family of languages: Proto-Germanic *strikan- → Old High German 'strihhan' → German 'Strich' (a line or dash), and Proto-Germanic *strikan- → Old Norse 'strika' → Modern Swedish 'streck' (a line or mark). English was part of this same family, so 'streak' and its cousins all share the same ancestral idea of something drawn or pressed along a surface.
In its earliest English uses, a streak was almost always something you could see — a physical mark or line, like a stripe of colour in a piece of stone, the trail of a finger drawn through dust, or a vein of mineral running through rock. Miners in particular used the word when they described the colour that a mineral left when scraped across a rough surface, and this geological sense still survives in chemistry and earth science today. The word carried a strong visual quality; it described something narrow, directional, and distinct from what surrounded it.
Over the centuries, the meaning of streak quietly expanded. By the 16th and 17th centuries, writers were using it more loosely to describe any thin line or band of light, colour, or texture — a streak of lightning across the sky, a streak of red in a person's hair, or a pale streak of dawn appearing on the horizon. The word had a natural poetic energy because it captured both the shape and the speed of things: a streak was not just a line, it was a line that seemed to have been made quickly, almost violently, by something in motion.
The figurative use of 'streak' — meaning a period or run of something, especially luck — developed considerably later, appearing in common use from around the 18th and 19th centuries. A 'winning streak' or a 'losing streak' transferred the visual idea of a continuous, unbroken line onto the experience of time: just as a streak of colour runs uninterrupted across a surface, a streak of luck runs uninterrupted through a series of events. This extension from space to time is a very common pattern in English, and 'streak' made the jump with remarkable elegance, keeping its sense of something vivid and unmistakable.
The verb 'to streak', meaning to run naked in a public place, became popular slang in the 1970s, particularly during the craze for this behaviour at sporting events and on university campuses. This sense drew on the older meaning of moving very fast — to streak across somewhere was to move in a fast, straight line, like a beam of light. The nakedness added an element of social surprise, but the word's movement through centuries shows something wonderful about how language works: a simple Old English mark made by a finger on a surface eventually gave English speakers a way to describe lightning, lucky runs, and daring dashes across cricket pitches.