"Red wave," or "crimson wave," is a euphemism for a woman's menstrual period. The term refers to the menstrual blood and is used in common phrases like "surfing the red wave" or "riding the crimson wave". This slang is used to discuss periods, which have historically been a taboo subject, though the phrase itself originates from the 1990s movie Clueless.
Origin: The phrase was popularized in the 1990s teen movie Clueless, where the character Cher uses it to tell a teacher she has her period.
Euphemism: It is one of many euphemisms used to avoid directly naming menstruation, alongside others like "shark week" or "that time of the month".
Modern usage: The term continues to be used in modern conversations and campaigns to help normalize discussions about menstruation.
Color: The color of menstrual blood can be bright red, especially at the beginning of the period when it is fresh.