It's one of those songs that can mean anything that you want. The word "yellow" was inspired by the fact that the guy that wrote the lyrics was thinking of a word to use and noticed the Yellow Pages (no kidding!). The Yellow Pages is a telephone books which groups telephone numbers by the type of business. If I didn't know that, I would think yellow referred to the color of the sun and starts when they shine. It would make at least as much sense as anything else.

Yellow means " the colour yellow".

yellow = the colour yellow

Yellow is 1) a person that it is shy or fearful and 2)the colour yellow

"Yellow", by Coldplay. Honestly, I think the meaning is open to your own interpretation. In English, "yellow" is often connected with cowardice, but this meaning doesn't apply to the Coldplay song.