Architectural and Engineering Glossary



A beam whose section has the form of an inverted L;usually placed so that its top flange forms part of the edge of a floor.


That portion of a precast concrete frame composed of the column,haunch, and part of the girder.


Same as angle iron.


A plan having the shape of a capital letter L.


A shore having an L head.


Abbr.for “lime and cement mortar.”

Label Course

A course, 1 of bricks around the exterior perimeter of the visible face of an arch; placed so as to throw off rainwater that would otherwise run down the face of the wall.

Label Molding

label A square arched dripstone or hoodmold; extends horizontally across the top of an opening and returns vertically downward for a short distance.

Label Stop

1.The termination of a hoodmold or arched dripstone in which the lower ends are turned away from the opening horizontally. 2.Any decorative boss or other termination of a dripstone, hoodmold, sill, etc.; a knee 

Labeled Door

A fire rated door carrying a certified rating by the Underwriters’ Laboratories, Inc

Labeled Frame

A doorframe that conforms to all applicable requirements and tests of the Under writers’ Laboratories, Inc., and bears their label.

Labeled Window

A window that conforms to all applicable requirements, in respect to fire resistance, of the Underwriters’ Laboratories, Inc., and bears their label designating the fire rating.

Labor And Material Payment Bond

A bond of the contractor in which a surety guarantees to the owner that the contractor will pay for labor and materials used in the performance of the contract.The claimants under the bond are those having direct contracts with the contractor or any subcontractor.

Labor Cost

On a construction project, the cost of all labor necessary to produce the construction required by the contract documents.


1.A maze of twisting passageways. 2.In medieval cathedrals, the representation of such a maze inlaid in the floor. 3.A garden feature of convoluted paths outlined by hedges, usually above eye level; also called a maze.


A resinous insect secretion used as a base for shellac, lacquer, and varnish.


A coarse grained wood from Australia, pale pink to pinkish brown in color, moderately hard and heavy, with a lace like figure; used for interior trim, paneling, and plywood.


Architectural decorations resembling lace. Also see cast iron lacework and jig  saw work.

Ladder Ditcher

See ladder trencher.

Ladder Jack Scaffold

A light duty scaffold supported by brackets attached to ladders.

Ladder Trencher

A ditcher which digs trenches; utilizes buckets mounted on a pair of chains that travel on the exterior of a boom.

Ladies’ Room, Women’s Room

In a public building, a room containing toilet and lavatory facilities for the use of ladies.

Ladkin, Latterkin

A pointed piece of hard wood used for clearing out the grooves of the cames, which hold panes of glass in stained glass windows and casements.


In Spanish Colonial architecture and derivatives, an adobe brick that has been kilndried rather than sundried, thereby providing increased durability, increased mechanical strength, and greater moisture protection.

Lady Chapel

A major chapel dedicated to the Virgin Mary, on the axis of a church at its east end.


On drawings, abbr. for lagging.

Lag Bolt, Coach Screw

A bolt having a square head and a thin, coarse pitched thread.

Lagged Pile

A pile having longitudinal pieces (i.e., lags) which are fastened to it for providing mechanical protection and increased friction and bearing area.


1.Thermal insulation for pipes, tanks, ducts, etc.; sometimes block insulation, pre shaped to conform to  the curved surface. 2.The planking, consisting of narrow strips, extending from one rib of the centering of an arch or vault to another; provides direct support for the voussoirs until the arch or vault is closed in. 3.Boards which are joined, side by side, lining an excavation. 4.Horizontal members between soldier piles.5.Wood strips that cover a wall.

Laid-dry Masonry

Same as dry masonry.

Laid-on Molding, Planted Molding

A molding that is worked separately and fastened to the work by brads.


The accumulation of fine particles on the surface of fresh concrete resulting from an upward movement of water in the concrete; occurs when excessive water is used in the mix- ing of the concrete.


In Spanish architecture and its derivatives, same as flagstone.


Any of a number of bright pigments which are prepared from animal, vegetable, or coal tar coloring matter, or formed synthetically; used in paints.

Lake Sand

Sand consisting mainly of rounded particles as contrasted with bank sand which has sharp edges; the latter is preferred in plastering.

Lally Column

A proprietary name for a cylindrical column which is concrete filled; used as a structural column to support beams or girders.


On drawings, abbr. for laminate.


The monumental human headed, winged bulls that guarded the entrances to Mesopotamian palaces and temples.

Lamb’s Tongue

1.The end of a handrail which is turned out or down from the rail and curved so as to resemble a tongue. 2.A carpenter’s molding plane having a deep and narrow blade more or less resembling a tongue and curved so as to cut a quirk bead.3.A molding cut from such a plane, usually two ovolos separated by a fillet and set off by fillets at the other ends.


A unit of luminance equal to (1/) can- dela per sq cm; equal to the uniform luminance of a perfectly diffusing surface emitting or reflecting light at the rate of 1 lumen per sq cm. Abbr. L.

Lambert’s Cosine Law

A law stating that the luminous intensity, in any direction from a plane surface, varies as the cosine of the angle between that direction and the perpendicular to the surface.


An ornamental horizontal band, often fringed, lobed,or notched along its lower edge.


A reinforced concrete, metal, or wood member joined with similar members in a criss cross pattern so as to form an arch or vault.

Lamella Roof

A vaulted roof-framing system composed of lamellae.


1.A product made by bonding together two or more layers of material, e.g., plywood, laminated wood, etc. 2.To unite layers of material with an adhesive.

Laminated Arch

A wooden arch made of several layers or laminations of thin boards bolted or glued together.

Laminated Beam

A beam built up by gluing together several pieces of timber; may be either straight or curved.

Laminated Glass, Safety Glass, Shatterproof Glass

Two or more plies of plate glass, float glass, or sheet glass, bonded to a transparent plastic sheet between them to form a shatter resisting assembly.

Laminated Plastic

A plastic material consisting of superimposed layers of a synthetic resinimpregnated or resin coated filler which have been bonded together (usually by means of heat and pressure) to form a single piece.


An incandescent lamp, usually with a PS-or A-shaped bulb which is silvered from the maximum diameter to the  base,leaving a clear or frosted hemispherical region opposite the base end.