Lagging

lagging [′lag·iŋ]

(civil engineering)

Horizontal wooden strips fastened across an arch under construction to transfer weight to the centering form.

Wooden members positioned vertically to prevent cave-ins in earthworking.

(cell and molecular biology)

Pertaining to chromosomes that show little or no movement during metaphase and anaphase of meiosis or mitosis.

(materials)

Asbestos and magnesia plaster that is used as a thermal insulation on process equipment and piping.

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lagging

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.

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Lagging 

a lumber product cut to size; produced from the side of a log by sawing. If the convex side of the lagging is not sawed through or is sawed through for less than half of its total length, the product is called side lagging; if the convex side is sawed through for more than half of its length, the product is called board lagging. Lagging is used to make scaffolding, centering, and support material.