What is the meaning of Screamo?

A genre of aggressive lo-fi guitar-driven music with predominantly screaming vocals, while preserving structural aspects of the emocore/hardcore emo genres of the early 1990's.

A genre of guitar-driven music combining late 1990's emo indie rock with interludes of screaming vocals, often accompanied by hardcore or metalcore guitar riffs.

Any punk rock-inspired music that involves screaming vocals, typically referring to the genres described above as well as certain subgenres of hardcore punk.

Source: wiktionary.org