Concise Bible Dictionary:

City in Egypt; the LXX has Σάϊς, and the Vulgate (as in the margin), Pelusium. Ezekiel calls it “the strength of Egypt” (Ezek. 30:15-16). It is supposed to be identified with the modern Tineh, where a few ruins are found. It is close to the Pelusiac mouth of the Nile, about 31° 4' N, 32° 28' E.

Jackson’s Dictionary of Scripture Proper Names:

thorn: clay: mire

From Anstey’s Doctrinal Definitions:

As a rule in the New Testament epistles, “sins” (plural) refer to the evil deeds that men do, and “sin” (singular) is the fallen nature in men (the flesh). Hence, “sins” are evil actions, whereas “sin” is the evil nature. The first is what we have done, and the second is what we are. Thus, “sins” are manifestations of “sin;” or “sins” are the product of “sin;” or “sins” are the fruit of a bad tree and “sin” is the root of that bad tree. “Sin” is more than just the old sin-nature; it is that evil nature with a will in it that is determined to gratify its lusts.
Another difference between these two things is that “sins” can be “forgiven” by the grace of God (Rom. 4:7), but “sin” is not forgiven, but rather, it is “condemned” under the righteous judgment of God (Rom. 8:3). It is important to pay attention to this distinction when reading the epistles; if we don’t, we will come away with some mistaken ideas.