The act of screaming pointless and/or meaningless lyrics at an ear-bleeding volume to the point where you want to rip the singer's vocal chords out. In order to make the "music" sound hardcore, the drummer uses the double bass exclusively throughout each song and the guitarist plays the same power chords. Some jokes er-I mean bands include:
From First to Last
Bring Me the Horizon
The Devil Wears Prada
The Number Twelve Looks Like You
Heavy Heavy Low Low
Fear Before The March of Flames
Drop Dead, Gorgeous

People often label bands as screamo when they scream but most of the time they're wrong.

Screamo died in the 90's... RIGHT..
but now new bands started to play like a comercial screamo
that is kinda good actually...
saetia, orchid, Reversal of a man, are/were good screamo bands.
Orchid is actually Hardcore Punk, but fuckin fags keep telling that's screamo when it's not.
Screamo has "turned" into a new genre... that is mixed or confused with Screamocore:
bands as underoath, haste the day(at it's beginnings), shaped by fate, symphony in perfil, norma jean (garbage screamo/grunge screamo) are screamo bands NOW.
bands like atreyu and the bled are "hardcore".

bands like alesana and finch a part from being gay are fuckin pop... those cock suckers suck.
New Screamo is characterized by vocals and some parts of singing, melodic guitars, continous drumming and a elaborated music that put up together sounds better.
And ZAO is NOT A screamo band!. that's hardcore/metal

and please don't fucking mix: emo, emocore, violent emo, southern rock, hardcore, metalcore, WITH FUCKING SCREAMO!

1. A series of screams and belches, usually performed by homosexuals.
2. The audio track from a bestiality porn
3. The moans from bears having sex inserted onto a background of random unpleasant noise, some may classify it as music, i prefer the term noise.

It as nothing to do with emo. It's true that the name screamo looks like scream and emo, but it's not emo with scream.
Screamo is a lot more musicaly violent than emocore.
Listen to Saetia or Circle take the square (both best screamo band), and tell me if it sound like Alexisonfire or the used. Those are emo core.. far smoother than screamo.

A type of music very similar to post-hardcore except more influenced by "emo" music. Combines emotional singing with screaming and grunting. The favourite music of scene kids and most emo kids.

1. Screamo is REALLY a type of music that died out in the 90's. It is NOT screaming emo.
2. Today, most people DO think screamo is screaming emo. If somone says they listen to screamo now days, they most likely mean they listen to emo music with more yelling.

Very fast played music, with very angry lyrics and twisted stories. Nothing to do with finch and all that crap. Screamo is an art form. Could I suppose be classified as noisecore to some people.