1.
cheering squad; pep squad; cheerleading team
An organized group that leads cheers and encourages athletes or competitors, especially at school sporting events. In Japan, traditional 応援団 are known for their military-style discipline and coordinated chants.
2.
support group; group of supporters; fan base
More broadly, any group of people who actively support a person, team, cause, or organization.
Composed of 応援 (support/cheering) + 団 (group/team). Japanese school 応援団 are distinctive: they typically feature a 団長 (squad leader) in a traditional long coat who leads synchronized chants and gestures, quite different from Western cheerleading.
Common collocations
Cultural note
Traditional school 応援団 are known for strict hierarchical discipline, loud rhythmic cheering, and distinctive uniforms (often a long black coat called 学ラン). They are a staple of Japanese school culture and appear frequently in manga and anime.