The most common definition that you will most likely hear is the species level, but I don't think you will get much mileage out of this one as the kind as described in xian mythology appears to have categories that include obviously different species as the same kind.
AIG writes:
Creationists would like to define kind in terms of interbreeding, since the Bible describes different living things as multiplying after kind,
Speciation, Yes; Evolution, No
| Answers in Genesis
or some creos believe:
CreoWiki writes:
Hypothesized kinds
Creation biologists have proposed a number of possibilities for the created "kinds":
Humanity Creationist Sigrid Hartwig-Scherer concluded that H. erectus/ergaster, Neandertals and H. sapiens were members of the same basic type (which corresponds to a monobaramin) Homininae with the fossils called Australopithecus afarensis, A. anamensis, A. africanus, A. robustus, A. aethiopithecus, A. boisei and possibly Ardipithecus ramidus assigned to another basic type, Australopithecinae.
Felidae Creationists from Creation Ministries International and the Institute for Creation Research have proposed that the original kinds were comparable to the Liger and the Tigon.
Canidae Similar to the kind associated with cats, it is proposed that all canines had a common ancestor.
Camelidae Including both the camel and the llama, which are reproductively compatible, their hybrid offspring being known as "Camas."
Bovidae Including Cattle, Buffalo, Bison, and Yaks.
Equidae Including Horses, Zebras, and Asses.
Caprinae Including Sheep, Goats, and ibex.
Crocodilia Including all the varieties of alligator, crocodile, and gharial.
Elephants African and Indian elephants can hybridize yet they are not even classified in the same genus.
Thus the created kind corresponds roughly to the family level of taxonomic classification, and possibly even the order with the notable exception of humanity.
Created kind - CreationWiki, the encyclopedia of creation science