1. A line, mark, smear, or band differentiated by color or texture from its surroundings.
2. An inherent, often contrasting quality: "There was a streak of wildness in him" (Olga Carlisle).
3. A ray or flash of light: the first streaks of dawn; a streak of lightning.
a. A brief run or stretch, as of luck.
b. An unbroken series, as of wins or losses.
5. Mineralogy The color of the fine powder produced when a mineral is rubbed against a hard surface. Used as a distinguishing characteristic.
6. Botany Any of various viral diseases of plants characterized by the appearance of discolored stripes on the leaves or stems.
7. Microbiology A sample of microorganisms that has been introduced into a solid culture medium by a needle drawn across its surface.
v. streaked, streak·ing, streaks
1. To mark with streaks: rain streaking the pavement.
2. To make streaks of a different, usually lighter color in (hair) using a chemical preparation.
3. Microbiology To inoculate (a culture medium) with a streak.
1. To form streaks.
2. To be or become streaked.
3. To move at high speed; rush.
4. To run naked in public, especially as a prank.
[Middle English streke, line, from Old English strica; see streig- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.