Definition of "Bats"

The Dark Knight Returns, published in four installments in 1986, is an extremely grim vision of a near-future Batman in a crime-ridden Gotham (reminiscent of Death Wish–era New York) that went to seed after Bats hung up the cape and cowl years prior.

2014 July 23, Abraham Riesman, “Dear Hollywood: Stop Using Frank Miller’s Batman Stories As Source Material”, in Vulture‎