Anarthrous nouns
From Textus Receptus
Anarthrous nouns are generally translated into English with the indefinite article ("a, an"). There are some anarthrous nouns which are qualitative and are often translated without an article. "Anarthrous," in grammar, simply means without the article. In English we have both the definite article (‘the’) and the indefinite article (‘a’), but in Greek there is no indefinite article.