Jerome: What Exactly is Heathen Language?

After the surprising use of "heathen/gentili" I noted before, I have kept an eye out for further uses of the term. In each of the two letters by Jerome that are a part of my reading for the next segment of history, he noticed the word once. In Letter 52 to Nepotian, he transitions from quoting Virgil to quoting the Bible by calling the former "heathen literature" (Chapter 2). In this case the foreignness of the poetry is not being in Latin, as all of the letter Jerome writes is in Latin, but it being pagan. Clearly, this does not explain why he would call Aramaic/Syriac—a Biblical language—"gentili." The other reference I note is in Chapter 16 of Letter 54 to Furia. There, Jerome talks about how the prophet Elijah helped a "heathen widow." Again, the meaning is in pagan, but whereas, at least from Jerome's perspective, Virgil is "foreign" for not being Christian, the widow can only be not Jewish. (I realize Virgil died a few years before Jesus was born, but his the life of his poetry was mainly after the advent of Christianity, by numbers.)

In any case, these two examples both have Jerome using the word as synonymous with paganism, in which cases "heathen" is an appropriate translation, if still more derogatory than he seems to intend. "Mammon," however is a word that is part of a language spoken by Jewish people and early Christians, very much including Jesus. Thus, rather than finding other instances of the word elucidating the previous use, it has only added to my confusion.

A different translation of all Jerome's letters is at the Christian Classics Ethereal Library.