A boiler room can refer to different things depending on the context. Here are some of the most common meanings:

• Boiler room (building): A room or space in a building for mechanical equipment and its associated electrical equipment.

• Boiler room (business): A busy center of activity, often selling questionable goods by telephone.

• Boiler Room (music broadcaster): An online music broadcaster and club promoter based in London, United Kingdom. It hosts predominantly dance music events, focusing on underground genres, in locations internationally, and broadcasts the shows live over the internet).

• Boiler Room (music project): A music project launched in London in 2010 that films DJs playing music in a small, intimate setting, often in a boiler room, and broadcasts the footage live over the internet. The project aims to showcase underground and up-and-coming DJs and musicians).

• Boiler room style: A term used to describe a type of DJ set where the DJ booth is on the dance floor without anything separating the crowd from the DJ. It is often characterized by minimal lights, no screens, and a 360-degree setup. The term comes from the idea of a club being so packed that people have to hide in the boiler room to hear the DJ.

Overall, a boiler room can refer to a physical space in a building or a type of business activity, but it can also refer to a music broadcaster or a type of DJ set.