Agape: The Love of God in Bloomington, MN

Just what is agape? The Apostle John says that God is agape. What does that mean? Also, is only God agape? Since agape is a Greek word, how does this concept fit into their society? I understand that they had many gods. Just what is the meaning in comparison with other Greek words for love? Does agape really mean "love" in any sense of the word?