Twist Lock - 4. A soundman term for what lighting folk would call a NEMA L14-20 or L14-30 connector.
PowerPARTS Wiring Devices: 30A 125/250VAC NEMA L14-30 Locking Male Plug | Lex Products
PowerPARTS Wiring Devices: 30A 125/250VAC NEMA L14-30 Locking Male Plug | Lex Products