In Japanese internet slang, “草 kusa” means laughing. “草” itself means “grass.” So, why do we use “草” to mean laughter?

Laughing in Japanese is “笑う warau.” On computers and smartphones, “lol” in English is written “w” taking the first letter of warau. Eventually it has become common to use multiple ws and write “www” to indicate laughter. “www” looks like grass, so today laughter is called “草” in Japanese internet slang.

This only applies to Japan, and it is important to note that even if the same kanji are used, they can have completely different meanings in China.

In Chinese slang, 草(cǎo）is equivalent to English fxxk! Check out this short video based on this:

In Chinese, the character “草” also means grass. However, the same kanji characters are pronounced differently in Japanese and Chinese. In Chinese, “草” is read cǎo. This reading is the same as the reading of a character that means “fxxk.” The character is 肏 cào. Although the tones are different, the sounds are very similar and so 草 is  used as secret language for 肏. 

So be careful when writing Chinese characters on the internet! Even if you are comfortable with Japanese, they can mean unintended things in Chinese.