Our English word "love" is actually 3 very different words in the Bible -- meaning very different things. What are they?
The first is phileo -- this means brotherly love. It is the kind of friendship and love you might have for a sister or brother or family member. Our city Philadelphia -- the city of brotherly love -- is an example of this.
The second is eros. This is sensual or romantic love. You can think of English words associated with this; it is the type of love between lovers or husband and wife, including physical affection.
The third and most eternal is agape. Agape is God's love. It is selfless and thinks of the other's benefit and welfare. It gives of itself and thinks of what is best for the one who is loved. When the Bible says "God is love", it is this kind of love that is the very nature of God.