“An equally valid translation for the word basileia (although it doesn’t have many historical connotations because we haven’t used it as much) is the “reign of God.” The important denotation is the issue of control, command, oversight, having “a Lord” as organizing principle.” from “Jesus’ Plan for a New World: The Sermon on the Mount” by Richard Rohr, John Bookser Feister

Basileia is the Greek word for Kingdom.