The belt that a Taekwondo student wears carries a lot of meaning.
It indicates their length of training and level of knowledge. Each color is also symbolic of astage of growth and development as a martial artist.
The meaning of each belt color is as follows :

 

White Belt Representative of purity, a new beginnnig and no prior knowledge of Taekwondo. Yellow / Orange Belt Signifies the Earth from which plants grow. Similarly this stage is the foundation and beginning growth stage of the Taekwondo student. Green Belt A green plant is one that is already reaching up and out, growing in strength and maturity. The green belt level symbolizes a more solid level of skill and ability. Purple / Blue Belt Represents the sky and new heights. The blue belt student the blue belt student continues to progress in skills both physical, mental and emotional. Brown Belt Represents plants growing and rooting in the Earth, stabilizing physical and mental power. This stage represents an advanced stage of the Taekwondo students growth. Red Belt Represents the sun, a source of tremendous power and energy. The color red is also universally symbolic of danger and caution. At this level a Taekwondo student should have great strength and confidence. This must be balanced with self-control and humility. Black Belt The opposite of white, it represents proficiency and maturity. It also marks the end of one path (the color belt ranks) and beginning of whole new level of training (the pursuit of advanced Black Belt ranks).