The BBC's business reality show known as Dragon's Den in the United Kingdom is titled Dragons' Den.
The British title uses the plural possessive “Dragons'” because the programme centres on a group of investors called Dragons. Entrepreneurs enter the Den and present their businesses while asking for investment in exchange for equity. The title therefore describes the setting as a den belonging to several investors.
The spelling is easy to mix up with the singular “Dragon's Den,” which is also widely used in ordinary speech and in the topic label. The official British programme title is conventionally written “Dragons' Den.” The punctuation distinguishes the plural group from one individual Dragon.
The title also differs from names used by international adaptations. The American version is called Shark Tank, while other countries have their own localized titles. These programmes share the same broad investment-pitch format, but their names and panels are not interchangeable.