Screaming Vocals
Screaming Vocals is a type of singing that involves the person to distort their voice to either a high-pitch-crackling, a low-pitch-growling, or just straight up yelling while following along a type of rock music. It started off with the 70's and 80's metal groups Black Sabbath, The Who, and Kiss, and also Metallica.
The Meaning
Metal groups say "metal" is the music of evil and anger, and "screaming fits it well. However, some bands with "screaming" vocals just do it to follow along with the flow of rock music that is around. Quiet Riot vocalist Kevin DuBrow is the known for his high-pitch growling at the microphone, and started the high-pitch screaming in music. DuBrow says "I started it when I was 14. I was practicing singing and I made my voice go really high-pitch. I wanted to go even higher, so I tried. The ended up screaming really high-pitched. It didn't hurt. I liked it more than singing."
Opinions
Some people say it is annoying, and devilish.