Bamboo is not a wood but a plant. Its veneer originates from the stems of plants. 

Bamboo is one of the fastest growing plants in the world. A stem can be harvested after 5 years. After harvesting, the bamboo stalks are split and the outer skin is removed. The strips are naturally light yellow in color (natural), but can be steamed to a light brown (caramel) color. After processing and drying, the strips are ready to be processed into the finished product in various ways. 

What does "side pr" mean?

The strips are placed vertically next to each other and glued together. This creates a fine line pattern in which the roots of the bamboo are subtly visible.