An ACA-registered dog is a dog that is listed under the American Canine Association's registry. Dog registries in general list dogs for the purposes of breeding and exhibition. They do not accept mixed breed dogs or animals of unknown heritage.
The ACA is not one of the Domestic Registry Organizations accepted by the American Kennel Club (AKC) for application to the AKC's own registry; however, dogs registered with the AKC can be cross-registered with the ACA afterward. The ACA considers itself a service registry and offers a worldwide lost-and-found tracking service as well as seminars, genetic tracking and the usual breed exhibitions and trials.