- The act of regenerating or being regenerated.
- In electronics, a positive feedback process in which amplified energy is fed back as an input.
- In Doctor Who, the process by which a Time Lord is able to take on a new physical form. Used when a new actor is cast as The Doctor.
Season 8, Episode 15 - The Comic Book Store Regeneration
Aired February 19, 2015
As they prepare for the reopening of Stuart's comic book store, the gang is at each other's throats. Sheldon is upset that Amy helped Barry Kripke with his work, so Penny tries to teach him how to let things go. When Sheldon reveals that Amy has been performing experiments on her, Penny struggles to follow her own advice. Howard is angry at Stuart over the furniture in his shop.
When they go to collect food for the store's grand opening, Leonard and Raj think they spot Firefly star Nathan Fillion. Later, Howard receives some devastating news about his mother, and the gang rallies round him.
Season 10, Episode 22 - The Cognition Regeneration
Aired April 27, 2017
Fearing his mind is not a strong as it once was, Sheldon decides to improve his cognitive function by learning new tasks including baking, juggling and riding the unicycle.
Meanwhile, Leonard is not impressed when Penny is offered a job by her ex-boyfriend, Zack.
Season 11, Episode 6 - The Proton Regeneration
Aired November 2, 2017
When Sheldon learns that Professor Proton's show is being redeveloped, he decides to audition for the role and ends up in competition with Wil Wheaton. Meanwhile, Penny takes care of Halley when Howard and Bernadette are put on bed rest.