The “Arrowverse” is the name for an expanding collection of DC Comics-based superhero TV shows all of which are interconnected. The shows were developed for broadcast on the CW Network (Co-owned by CBS and Warner Brothers) in the USA. While the individual showrunners and creative teams change, often with every season, the Arrowverse programs are all created in part by Greg Berlanti, who’s company produces them for Warner Brothers Television.
Arrow debuted to strong ratings and extremely positive reviews in 2012. In 2013, season 2 of Arrow introduced the character of Barry Allen/The Flash, who subsequently spun off into his own show, The Flash.
In 2015, Berlanti co-created Supergirl with Alison Adler for broadcast on the CBS network. CBS did not initially intend Supergirl to be part of the Arrowverse. They did, however, allow one crossover between Supergirl and The Flash. In season 2, Supergirl was moved to the CW for budgetary reasons, and the show became more integrated into the Arrowverse with regular crossovers.
Berlanti has co-produced one additional superhero show for the CW: 2018’s Black Lightning. Black Lightning was not conceived as part of the Arrowverse. However, in 2019-2020’s crossover event, “Crisis on Infinite Earths,” the character of Black Lightning was announced as appearing. It is yet to be confirmed that show is connected to the Arrowverse.
Arrowverse Wikipedia page
The Ωmega Beam pages for Shows confirmed to be part of the Arrowverse: