What does “Satan” mean?

It is a Hebrew word meaning “the enemy” (the Old Testament was written in Hebrew). Sometimes it is translated “the enemy” or “opponent”, or (in the King James translation) “adversary” and sometimes it is used as a name. Peter opposed the Lord Jesus, so Jesus said to Him: “Get thee behind me, Satan”. Human nature is God’s greatest enemy (and ours too!), so the New Testament calls it “Satan” in many places. Wicked men are also referred to as “Satan”, in some verses.

There are a few Bible passages that are commonly interpreted as teaching a supernatural devil, but in every case this is due to careless reading. For example, “Lucifer” of Isaiah 14:12 is not a wicked angel. He is the king of Babylon, a very wicked, cruel and proud man. Read the whole passage, starting from verse 4. Likewise, the “anointed cherub” of Ezekiel 28:14 is not a wicked angel. It is the king of Tyre —verse 12 says so.