Red

The colour red. It symbolizes many different things; aggression and anger, love and romance, but at the heart of it all, I believe it represents blood. Whether it be the red of one's face as your emotions rise, or the red as a result fierce battle, much of the meanings associated with the colour red come down to the idea of blood. It is something that ties most of the worlds living creatures together and it keeps all alive. The colour red, the colour of blood.

 

(Note: I am not actually trying to be morbid or anything - it's just the first thing that I thought of when I heard the word 'red'.)