Meaning:
Literally translated as “the waves behind,” this term comes from a Chinese saying “In the Yangtze River, the waves behind drive on those before,” which uses “waves” as a metaphor. The saying compares the flowing of the river to the ceaseless changes brought by new people and new things with the lapse of time. Therefore, “the waves behind” often refer to “the young generation.” The term became a buzzword after the streaming site Bilibili released a short video to mark the Youth Day (May 4 in China) which quickly went viral. In the video, middle-aged actor He Bing praised the courage, open-mindedness and creativity of young people, addressing them as “the waves behind.”
Example:
A: 你看了B站的视频《后浪》吗？
Nǐ kàn le B zhàn de shìpín 《hòulàng 》ma？
Did you watch the short video titled “The Waves Behind” released by Bilibili?
B: 看了，这个视频很多人夸，也有很多人吐槽。
Kàn le，zhège shìpín hěnduō rén kuā，yěyǒu hěnduō rén tǔcáo。
Yeah. Many people praised it, and many others criticized it.