Enthiran (transl. Robot) is a 2010 Indian Tamil-language science fiction action film co-written and directed by S. Shankar. It is the first installment in the Enthiran film series. The film stars Rajinikanth in the main dual lead role as a scientist and the robot he created. Aishwarya Rai Bachchan, Danny Denzongpa, Santhanam and Karunas play supporting roles. The soundtrack album and background score were composed by A. R. Rahman while the dialogues, cinematography, editing and art direction were handled by Madhan Karky, R. Rathnavelu, Anthony and Sabu Cyril respectively. The story revolves around the struggle of a scientist named Vaseegaran to control his sophisticated android robot named Chitti, after Chitti's software is upgraded to give it the ability to comprehend and exhibit human emotions and to commission it to the Indian Army. The project backfires when Chitti falls in love with Vaseegaran's girlfriend Sana, and is manipulated by Vaseegaran's mentor Bohra into becoming homicidal.

After being stalled in the development phase for nearly a decade, the film's principal photography began in 2008 and lasted two years. The film marked the debut of Legacy Effects studio (which was responsible for the film's prosthetic make-up and animatronics) in Indian cinema. Enthiran was released worldwide on 1 October 2010. Produced by Kalanithi Maran, it was the most expensive Indian film at the time of its release.

The film received generally positive reviews upon release. Critics were particularly appreciative of Shankar's direction, storyline, Rajinikanth's performance as Chitti, music, action sequences, production values and the visual effects by V. Srinivas Mohan. Enthiran emerged as the highest-grossing Indian film of 2010. It won two National Film Awards, three Filmfare Awards, seven Vijay Awards and two Screen Awards. Enthiran was followed by a standalone sequel, 2.0, which released in late 2018.