Okay, so you know how some boys like girls and some girls like boys? Well, there are also some boys who like other boys and some girls who like other girls. That's called homosexuality.
When people talk about someone being homosexual, they might also use other words, like "gay" or "lesbian". "Gay" means a man who likes other men, and "lesbian" means a woman who likes other women.
There are also some people who don't just like one gender or the other - they might like both! That's called "bisexuality".
It's important to remember that everyone deserves love and respect, no matter who they love. Love is a beautiful thing, and everyone should be able to express it with the person they choose.