Corrugated containers are made from corrugated board. The corrugated container is made by cutting and folding flat stock into the required dimensions.
Corrugated board is created by wrinkling or folding paper in a sine wave pattern, then using an adhesive to fix the wave pattern between 2 flat sheets of paper. The flat paper sheet on the exterior is called the liner, while the wrinkled interior sheeting is called the fluting. The pattern is best seen when viewed from the end of a sheet of corrugated board. Sheets can be of almost any dimension, depending on the size of paper stock used in the manufacturing process.
Corrugated board is usually rated by its crush resistance, the ability to withstand pressure applied to it. Many corrugated containers have their respective crush test rating printed upon the container, detailing how many pounds per square inch they will withstand before crushing.
Corrugated containers are ubiquitous in modern commerce, being both strong and economical. While not as strong as metal containers, they are quite well suited for most commercial packaging needs of dry materials. Corrugated containers are also available for packaging less than totally dry materials, after first being treated with wax, paraffin, or another dampness resistant material. Corrugated containers are generally a poor choice for liquid packaging, being susceptible to leakage and puncture.
Corrugated containers possess the advantage of being recyclable, an advantage shared by many paper products. Recycled paper is often remanufactured into brown kraft paper, the stock from which corrugated board is commonly produced. Corrugated board can be of other colors, depending on the requirements of the customer.
Corrugated board can be multi layered for additional strength. Very large corrugated containers called gaylords are often used for bulk shipments of materials ranging from peanuts to metal parts. The usage of corrugated containers is almost limitless.
Another commonly used paper stock used in the production of packaging is cardboard. It is not the same material as corrugated board. The common term cardboard box is often misapplied to corrugated containers.
Sources:
http://www.fefco.org/index.php?id=corrugated_board
http://www.tappi.org/paperu/all_about_paper/earth_answers/EarthAnswers_HowBoxes.pdf