A term applied to paper above an accepted weight, in the UK usually in the region of 220-225g/m2, but many countries make the distinction at 250g/m2.
However there are a number of grades of a weight below the 220-225g/m2 level which are known as boards. Printers boards are an example.
This is a general term given to boards for graphic purposes. One group are homogenous, that is to say, made on a paper making machine (Fourdrinier), of one furnish throughout. The second group are paste boards or laminated together.
Printers boards may be coated or uncoated, and of any furnish.