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 1×12-1’, a formula is used otherwise to determine equivalents.

BDL

Bundle.

BEV

Beveled machining, generally in siding, for example 1/2×8 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 1×4 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 2×4 and 2×6 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 4×4 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 4×4 = (4 “by” 4).