question: What fictional universe is aired on the CW for The Flash?
answer: Arrowverse
context: Title: Freedom Fighters: The Ray
  Passage: Freedom Fighters: The Ray is an upcoming American animated web series developed by Greg Berlanti and Marc Guggenheim.  It will debut in 2017 on The CW's online streaming platform, CW Seed and is based on DC Comics character Ray Terrill / The Ray, a reporter who gains light-based powers after being exposed to a genetic light bomb.  The series is set in the Arrowverse, the same fictional universe as "Arrow", "The Flash", and "Legends of Tomorrow", while also taking place on the alternate earth, Earth-X.
  Title: The Flash (season 4)
  Passage: The fourth season of the American television series "The Flash", which is based on the DC Comics character Barry Allen / Flash, follows a crime scene investigator with superhuman speed who fights criminals, including others who have also gained superhuman abilities.  It is set in the Arrowverse, sharing continuity with the other television series of the universe, and is a spin-off of "Arrow".  The season is produced by Berlanti Productions, Warner Bros.  Television, and DC Entertainment, with Andrew Kreisberg and Todd Helbing serving as showrunners.
  Title: Arrowverse
  Passage: The Arrowverse is a shared fictional universe that is centered on television series airing on The CW, developed by Greg Berlanti, Marc Guggenheim, Andrew Kreisberg, Phil Klemmer, and Geoff Johns, based on characters appearing in publications by DC Comics.  The shared universe, much like the DC Universe in comic books or the cinematic DC Extended Universe, was established by crossing over common plot elements, settings, cast, and characters.  The Arrowverse stars Stephen Amell as Oliver Queen / Green Arrow, Grant Gustin as Barry Allen / Flash, Megalyn Echikunwoke as Mari Jiwe McCabe / Vixen, with an ensemble cast leading "Legends of Tomorrow", including Arthur Darvill as Rip Hunter, Caity Lotz as Sara Lance / White Canary, Brandon Routh as Ray Palmer / Atom, Dominic Purcell as Mick Rory / Heat Wave, with Victor Garber and Franz Drameh as Martin Stein & Jefferson "Jax" Jackson / Firestorm.  Russell Tovey stars as Ray Terrill / The Ray.
citations: The Flash (season 4) Arrowverse