Adoration is a feeling of deep love. Some people may say animals don't have emotions, but you know from the adoration in your dog's eyes that it's just not true.
The noun adoration comes from the Latin word adorationem, which means "worship," particularly in a religious way. Adoration is still used today in a religious context, in phrases like "the adoration of God." If you adore or deeply love someone, you can describe that feeling as adoration. It's the kind of feeling Romeo had for Juliet, devoted fans have for a pop star, and you have for your beloved cat.