Distinguishing between insider and outsider groups and their differing nomenclatures is essential for accurate interpretation and translation. Jesus and his earliest followers, evidence demonstrates, were called `Israelites', `Galileans' or `Nazoreans' by their fellow Israelites. `Israel', `Israelites' were the preferred terms of self-designation among members of the house of Israel when addressing other members—not `'Ιουδαιος', `Jew' or `Judaism'. Modern interpreters and translators of the Bible, it is argued, should respect and follow this insider preference. 'Ιουδαιος , an outsider coinage, is best rendered `Judaean', not `Jew', to reflect the explicit or implied connection with Judaea. It was employed by Israelites when addressing outsiders as an accommodation to outsider usage. The concepts `Jew', `Jewish' and `Christian' as understood today are shaped more by fourth century rather than first-century CE realities and hence should be avoided as anachronistic designations for first-century persons or groups. Use of `Christian' is best restricted to its three NT appearances. The use of appropriate nomenclature is crucial for minimizing historical and social inaccuracies and misunderstandings.