Glossary of Wood Terms

Some types of wood are sold at a specific width and “per lineal foot” of length. This is in contrast to “per board foot,” which is a volume measure, and can be used to tally lumber of random widths

How Is Wood Measured? Wood comes in so many sizes and shapes, it is difficult to find a standard way to measure it. So, there are more than one type of measurement systems. Board Foot is a system to measure lumber by volume after it has been cut into boards, but before it is smoothed

Lumber size is often referred to as 4/4 (pronounced FOUR-QUARTER), 5/4 (FIVE-QUARTER), 6/4 (SIX-QUARTER), etc. This refers to the thickness of the lumber when it is first sawn and in its rough dimensions. 4/4 lumber is sawn in the rough to a full 1 inch. The size increases in 1/4″ increments. 5/4 lumber is sawn

FAS, or Firsts and Seconds, is the hardwood grade which includes the superior “furniture grade” hardwoods. This grade is typically free of defects, but some defects are allowed.

“RGH” indicates that the specified material is being sold as it came off the saw. It is in its “rough” state. This material is not planer-finished and will have no jointed edges.

What is S3S? The abbreviation “S3S” is a description of surface finish, usually pertaining to hardwood species. It stands for “Surfaced Three Sides”, which, as used in Goosebay’s hardwood lumber descriptions, indicates that two faces have been planed, and one edge has been processed with a straight-line rip saw, rendering the edge straight and smooth.

What is S4S? S4S is an abbreviation for “Surfaced on Four Sides”. It indicates a finish which renders both faces and both edges of a board planer-finished.

D4S indicates that the materials have been surfaced on all four sides.

S1S2E indicates that the material has been surfaced on two edges and one face, leaving the second face rough. See S3S.

Quarter sawn lumber has been cut through the heart of a log and thus the annular rings are perpendicular or 90º to the face of the board. 

Rift sawn boards are generally more stable than flat sawn but do not exhibit any quarter sawn patterns.

A flat sawn, or plain sawn,  board has a ring-to-face angle of 30º to 0º.  These are the boards sawn from the edge of the log and comprise  the least stable lumber in the log.