An ODM (original design manufacturer) is a company that takes the original specifications of another company or individual and builds the design to the product specifications.
ODMs make it possible for a company to get a product to market without having to completely design the hardware and without investing in production facilities. The ODM supplies manufacturing capacity. The company that created the specification typically retains ownership of the design.
White box servers, for example, are usually purchased in bulk quantities from ODMs. The ODM typically builds the equipment from commercial off-the-shelf (COTS) components that can be customized to some extent for particular environments. Although an organization could possibly do the same thing in-house, the ODM can manufacture and deliver customized servers faster and may also offer warranty protection for parts.
ODM is similar to the more commonly known term OEM (original equipment manufacturer).