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Glossary

Here is a list of common lumber industry abbreviations and terms, with definitions for each. If you have any questions, give us a call, or use our contact form to request assistance.

"
Inch or inches.
'
Foot or feet.
4/4, 5/4, 6/4, etc.
Nominal thickness in fractions of one inch.
AD
Air dried method of drying lumber to stabilize, minimize cracking/warping.
ADAT
Air dried after treatment for rot or fire resistance.
AYC
Alaskan Yellow Cedar, generally found in exterior Glulam in Denver area.
BD
Board.
BD FT
Board foot – measurement used in the industry. A “perfect” BF is a 1x12-1’, a formula is used otherwise to determine equivalents.
BDL
Bundle.
BEV
Beveled machining, generally in siding, for example 1/2x8 cedar bevel siding is 1/2" thick at the butt or thickest edge and tapers to approx 1/8".
BF
Board feet.
BH
Boxed heart, generally found in timber where the center of the tree (heart) is the middle of the timber.
Board
Usually a wood plank with a 1" (nominal) thickness.
BTR
Used in grading rules to indicate that the wood is at grade and “better”.
C/L
Carload - most framing lumber is shipped via rail cars.
CB
Center beaded machining detail, most often on paneling and siding.
CLF
Roman numeral “C” - hundred Lineal Feet, commonly used in molding costing.
CLIS
California Lumber Inspection Service.
CLR
Clear – meaning the board has no large defects and no knots on at least one edge and one side.
CM
Center matched veneers on plywoods.
CRA
California Redwood Association.
CV
Center “V” groove on a machined board.
DET
Double end trimmed, similar to PET.
DF
Douglas Fir species.
DF/L or DF-L
Douglas Fir/Larch.
DIM
Dimension.
DKG
Decking.
E
Edge.
E&CB2S
Edge & center bead 2 sides pattern on paneling.
E&CV1S
Edge & center vee 1 side on siding/paneling.
E&CV2S
Edge & center vee 2 sides on siding/paneling.
EB1S
Edge bead 1 side.
EB2S
Edge bead 2 sides.
EE
Eased or rounded edges on a finished product.
ES
Englemann spruce.
ESLP
Englemann spruce, lodgepole pine.
EV1S
Edge vee 1 side.
EV2S
Edge vee 2 sides.
FAS
Firsts & seconds – term used primarily in hardwoods indicating a 1st and 2nd grade of quality.
Fb or f
Term used to determine strength - fiber stress in bending.
FG
Flat or slash grain, grain running along the face of the board.
Fire Rated
Any item that has been manufactured, treated or designed to maintain a certain fire resistance.
FOB
Free on board, establish location where responsibility of load transfer in transportation of materials.
FOHC
Free of heart center, any board or group of boards not containing the center (heart).
FOK
Free of knots - uncommon, clear is the more common terminology.
FRT
Freight cost.
FSRGH
Full sawn rough - R/S is more commonly used.
G1S
Good 1 side, as in plywood.
G2S
Good 2 sides, as in plywood, MDO, etc.
GRN
Green, undried lumber - logs cut into boards or timbers.
H or M
Hit or miss planing, not a finished surface.
H&M
Hit & miss planning, not a finished surface.
HDO
High Density Overlay, type of plywood with a paper coating, most often a concrete forming panel.
Heart
Any portion of the board or timber containing the center portion of the tree. In redwood and similar species, the heart has a distinct color.
HF
Hemlock fir species of framing lumber.
HT
Heat treated to kill any insects and their eggs, most important on items for export.
I-JOIST
A manufactured floor joist, generally stronger than conventional lumber.
IC
Incense cedar species.
IG
Insulated glass.
IN
Inch or inches.
IND
Industrial (grade of particle board).
KD
Kiln dried – wood is placed in a kiln to dry quicker than air drying.
KDAT
Kiln dried after treatment – products dried (again) after application of chemicals for rot or fire resistance.
LAM
Items that are glued up in layers, laminated, as in LVL or plywood.
LGR
Longer.
LIN or LF
Lineal foot (feet).
LP
Lodgepole pine.
M
Roman numeral thousand.
MBF
Thousand board feet.
MC
Moisture content - percentage of water in any given piece of wood.
MDF
Medium Density Fiberboard – a denser, heavier version of particle board, machines to a great detail. MDF core is this product as a core to a hardwood plywood top veneer.
MDO
Medium Density Overlay - plywood where a paper coating has been applied to one or both sides.
MG
Mixed grain - grain pattern is a combination of flat and vertical graining.
MOE
Modulus of elasticity - measure of the amount of bend in a board or wood product.
MSF
Thousand square feet.
MSR
Machine stress rated - lumber tested to meet specific strength requirements.
NBM
Net board measure - net amount of lumber left after all machining, etc.
Nominal
Actual measurement of a board, i.e. a 1x4 actually may be 3/4" x 3-1/2".
NONCOM
Abbreviation for non-combustible lumber which has been treated to be fire resistant.
O
In windows, refers to the operating sash or portion of a given window.
O&ES
Oiled & edge sealed - an application placed on concrete form-ply.
OSB
Orientated Strand Board – panel product composed of wood chucks/strands placed, epoxied and pressed into a product as a substitute for plywoods.
PAD
Partly air dried - moisture content indeterminate.
Panel
Any sheet good item, including plywood, OSB, drywall and so on.
PET
Precision end trimmed - generally applied to “precut” studs, cut to a very exact length.
PP
Ponderosa pine
PT
Pressure treated - treated for rot or fire resistance.
PW
Paper wrapped bundles to protect the product during transit and storage.
R/L or RL
Random lengths, as in bundles containing a mixture of lengths. As opposed to most construction lumber where each length has been pulled into a separate bundle.
R/S
Resawn - a mill process to re-cut the wood to freshen the surface, create surface detail and/or cut to an exact customer requirement.
R/W or RW
Random widths - generally in the hardwoods industry, referring to bundles containing a assortment of widths of boards, including boards that are not standard “sizes”.
Rabbet
Slot/dado on lower edge of some sidings. This allows the top of the bottom board to fit into the bottom of the next board.
Radius Edge
Same as eased edge.
RGH
Rough.
RIS
Redwood Inspection Service - industry group regulating grades, specifically of redwood items.
RW/L
Random widths & lengths.
S-DRY
Surfaced dry.
S1E
Surfaced 1 edge.
S1S
Surfaced 1 side.
S1S1E
Surfaced 1 side, 1 edge - not common.
S1S2E
Surfaced 1 side, 2 edges - very common in cedar 1x boards.
S2E
Surfaced 2 edges.
S2S
Surfaced 2 sides
S2S1E
Surfaced 2 sides, 1 edge - not common.
S4S
Surfaced all four sides.
S4SEE
Surfaced 4 sides, eased edges.
SEL
Select - grade or process where better boards are pulled out from the total production.
SF
Square feet.
Shiplap
Pattern on sidings where the rabbeted edge of one board overlays the machined edge of the next.
SQ
Square as in foot. Is also very commonly used to measure roof/shingle area, i.e. 1 SQ = 100 square feet.
STD/STD&BTR
Standard & better - grade of most framing lumber in 2x4 and 2x6 sizing.
STR/STRUCT
Structural.
SYP
Southern yellow pine.
T&G
Tongue & groove pattern.
TAD
Thoroughly air dried.
Timber
Refers to any wood beam or post 4x4 or greater in size.
VG
Vertical grain - where the graining contained in a board runs straight up and down the board, parallel to the length.
Void
In plywood, places where knots fell out in a veneer creating a hole in that place.
WCLIB
West Coast Lumber Inspection Bureau.
WF
White fir.
WRC
Western red cedar.
WRCLA
Western Red Cedar Lumber Association.
WW
White woods - wood species including lodgepole pine, engleman spruce, etc.
WWPA
Western Wood Products Association - industry group controlling standards, grades, etc.
X
In windows, refers to an inoperable or fixed window.
Or, "by", as 4x4 = (4 "by" 4).