Pentecostalism is a type of Christian religion where people believe in being filled with the Holy Spirit.
Just like how you have your own energy inside your body that makes you able to run and jump and play, Pentecostals believe that the Holy Spirit can give them power to do good things and help people.
They also believe in speaking in tongues, which means talking in a made-up language that only they and God can understand. This helps them feel closer to God and communicate with Him better.
Pentecostal churches usually have lots of singing, praying, and clapping, and the people there are very passionate about their faith. They believe in following the Bible closely and staying close to God in everything they do.