The Singles Day (Chinese: 光棍节), or Double 11, is a Chinese shopping holiday that originated as an unofficial holiday for bachelors. The date, November 11 (11/11), was chosen because the number “1” resembles a “bare stick” (Chinese: 光棍, Guānggùn), which is a Chinese slang for a lonely man with no significant others, and four “1”s (the most that can fit into a calendar date if disregarding the year) abstractly refer to the demographic group of single men.  Read more on its Wikipedia page.