From the Wikipedia page 
A krai or kray (Russian: край, plural края́, kraya) was a type of geographical administrative division in the Russian Empire and in the Russian SFSR, and is one of the types of the federal subjects of modern Russia.
Etymologically, the word is related to the verb "кроить" (kroit'), "to cut". Historically, krais comprised vast territories located along the periphery of the Russian state, since the word krai also means border or edge, i.e., a place of the cut-off. In English the term is often translated as "territory". As of 2015 the administrative usage of the term is mostly traditional, as some oblasts also fit this description and there is no difference in legal status between the krais and the oblasts.