Love is a topic that is close to my heart. It is a wondrous and special emotion that can bring out the extremes of one's personality. Many people think of romantic love when ever the word is mentioned. Love, however, has many more facets. Let me take a moment to list the different forms of love that there are out there in the world:
I am of the opinion that our capacity for love is one of the traits that sets us apart from the other species. I believe that it is possible to describe the devotion of a pet for their owners as love, but I think it is a greater likelihood that it is pack oriented behavior projected upon the humans that is in the pets life. I don't think that this is some how diminishing the experience of love, only that we're anthropomorphizing the animal's experience and failing to consider it from their perspective.
If there can be no consensus on even one aspect of human emotion, how can we possibly begin to approach an understanding of an animal's emotions. Further more, it is an enormous act of hubris to claim that we can understand the emotions of a deity. They may speak to us but the do so in terms that we may understand. We will never fully comprehend the depth of love a deity may have for us.
Let's stop trying to play pin the meaning on the word (a lexographic version of pin the tail on the donkey) and accept that there are aspects of love that we'll never understand and are far greater then human conception. Only by accepting this can we begin to truly understand our own capacity for boundless, unconditional love.