Okay, so bisexuality is a way of describing somebody who is romantically and/or sexually attracted to people of their own gender and people of another gender. It's like liking both chocolate and vanilla ice cream, but in this case, it means that someone can like both boys and girls.
In the United States, there are lots of people who identify as bisexual, and it's becoming more common for people to talk about their bisexuality openly. This is a good thing because it can help people who are figuring out their own sexualities to know that there are other people who feel the same way they do.
However, not everyone is accepting of bisexuality, and some people might say mean or hurtful things to bisexual people. It's important to remember that it's okay to be who you are, and that there are people who will accept and love you no matter what.