redstreak
/ˈrɛdstreɪk/Definitions
1. noun
a streak or mark of red color, especially in the hair
“Her redstreak highlighted her otherwise dark locks.”
2. noun
a streak or mark, especially in the hair, caused by a split in the shaft of a hair, allowing the natural pigment to escape and form a streak or patch of a different color
“The redstreak in her hair was a result of years of using chemical hair dye.”