Screamo is a style of hardcore punk-influenced emo with screaming. Alex Henderson of AllMusic considers screamo a bridge between hardcore punk and emo. The term screamo is a portmanteau of the words "scream" and "emo." Screamo uses typical rock instrumentation, but is notable for its brief compositions, chaotic sounds, harmonized guitars, and screaming vocals. Screamo is characterized "by frequent shifts in tempo and dynamics and by tension-and-release catharses." Many screamo bands also incorporate ballads. According to AllMusic, screamo is "generally based in the aggressive side of the overarching punk-revival scene." Screamed vocals are used "not consistently, but as a kind of crescendo element, a sonic weapon to be trotted out when the music and lyrics reach a particular emotional pitch." Emotional singing and harsh screaming are common vocals in screamo.