etymology - How did the abbreviations 520 and 521 arise? - Chinese . . . The article explains that 520 means '20th, May' which is the day of a year designated as '网络情人节' (Online Valentine Day) since 2010 Thanks to the song 《数字恋爱》by 范晓萱, which used the term '520' to represent 'I love you' , people started to use this term the same way too It also stated in the next answer that '20-May' (520) is designated as the day for men to confess