What does the word "idol" mean to you? If you immediately thought about either a boy band or a girl band, chances are, you are either from East Asia or familiar with their culture. In the region, the word is widely used to describe either a boy band or a girl band. 

Then, who are they? What do they do? "Tokyo Idol" on Netflix features the life of Japanese idol Rio to help you understand them better. 

Young, aspiring J-pop idol Rio, 19, who wants to be a "singer" in the future, performs at small venues in Akihabara, Tokyo. Akihabara is a popular tourist attraction filled with shops that sell anime-related products, idol merchandise, games, and so on. (Basically, heaven for "Otaku") Not surprisingly, she sings anime music type songs while dressed like an anime character.

Every time she performs, about a dozen of her hardcore fans, mostly in their 30s and 40s, show up to support her. They wear flashy yellow T-shirts with the word "Rio" printed on them. They even gather at karaoke to practice chanting before her live starts.

Akihabara idols like Rio who are not signed by a major record label make money in various ways. The most noticeable event is greeting their fans, who bought their CDs, after their concert. Those fans pay another extra fee to wait in a line to briefly talk with their idols while shaking their hands. 

The documentary says, not a while ago, shaking a hand with a person of the opposite sex was considered sexual in Japanese culture.

So, are idols selling their sexuality? And are their fans sexually attracted to them?

Rio's hardcore fan Koji, 43, says he is not attracted to her. He feels energy and passion he didn't have when he was young whenever he sees her performance. And he wants to support her dream. Meanwhile, Naoyamumu, 23, says he's attracted to Amu, a 14-year-old idol.

In the end, Rio holds her solo concert for her 21st birthday. Her fans shed tears as she sings a song dedicated to them. Afterward, Rio, now signed to a major label, records her new songs with a famous J-pop producer. And the documentary ends.

Check out "Tokyo Idol" on Netflix if you are interested in the idol culture in Japan.