What does it mean to be human?

How can we define what it is to be human? We've been using the word 'Human' for so long... and yet we lack definition. The Merriam Webster Dictionary doesn't even have a definition of 'Human' without using the very word itself in that definition (http://www.merriam-webster.com/dictionary/human). I don't think any of the 'definitions' provided for the word can accurately display what it is. We all know we are more intelligent than animals. We created civilization. We created Technology. And we created computers that are just as smart as we are... but we're not computers are we? Because computers don't have emotions. Animals have emotions though... really all we are are very smart animals. We may not like to think of it that way because we like thinking we are superior. We enjoy the false belief that humans and animals are separate and different things. But a human is nothing but a species of animal. We may be more advanced, and we may be more evolved, but we are animals. The definition of human is very inaccurate, and we've lost sight of the fact that we are animals. Merriam Webster has several definitions of the word animal (http://www.merriam-webster.com/dictionary/animal). We as humans fit perfectly into the first definition, and yet the other definitions make sure that we humans are not animals, and we are superior... So if we don't have a basic definition as towards who we are... are we nothing? The human race has existed for less than 1% of earth's history... so maybe we are nothing. Nothing at all. And if we are nothing, how are we superior?