Definition of R2-d2

For the weapons system nicknamed "R2-D2", see Phalanx CIWS.

R2-D2 (called R2, or "Artoo" for short), is a fictional character in the Star Wars universe. R2 is one of the only four characters - the others being Anakin Skywalker/Darth Vader, Obi-Wan Kenobi, and droid companion C-3PO - to appear in all six Star Wars films. He and C-3PO are arguably one of the most famous duos in film history.