gang of four

Short definition from Wiktionary

Proper noun

1. 1
   Alternative letter-case form of Gang of Four.
2. 2
   A radical political faction composed of four Communist Party of China officials that came to prominence during the Chinese Cultural Revolution.
3. 3
   Any influential (political) group having four members.
4. 4
   Any influential (political) group having four members: Synonym of Big Four (“four largest corporations of Big Tech”).
5. 5
   An English post-punk band formed in 1976.