Since the trend of Twitter, then followed by Instagram, this # symbol becomes something common. Before that, we mostly see this symbol only on our landline phones.

Yes, this hashtag is used on social medias to tag a topic or keywords related to a post. But do you know that this # symbol has different names among different group of people? Guess what hashtag is called in Korea?

Among English Speaking Countries

In English this symbol is called a number sign or hash.

A different term used in America is pound sign.

Among Programmers

Programmers and those practicing IT tend to know # as sharp. Possible reason is because of a popular programming language C# (C-sharp).

Among Musicians

In music, there is ♯ notation which is named sharp. This notation adds half step higher to a note. The notation looks very similar to #, hence # is called sharp sign.

Among Indonesians

In Indonesia # is commonly called tanda pagar (fence sign) because it looks like common Indonesian house fences.

Among Koreans

Rather than a 해시태그 (hashtag), # is more commonly known as a 샵 (sharp).

Another term for # which is used more by older generation is 우물 정 (umul jeong) which means a (water) well. It comes from a hanja letter 井 (jeong) which is similar to # sign.