glass wool

American  

noun

1. spun glass similar to wool, used for insulation, filters, etc.

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glass wool British  

noun

1. fine spun glass massed into a wool-like bulk, used in insulation, filtering, etc

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Etymology

Origin of glass wool

First recorded in 1875–80

Example Sentences

Mid and East Antrim Borough Council said building regulations introduced in the 1970s led to the widespread use of safe insulation materials like glass, wool and fibreglass.

From BBC • Mar. 25, 2026

McKinley favored high tariffs on goods like steel, iron, glass, wool, sugar and beans as a way to protect and expand American industry.

From New York Times • Dec. 6, 2018

His chemicals go into refrigerators, glass wool, food boxes, bubble gum.

From Time Magazine Archive

The glass house also contains another important Owens-Illinois product: spun glass, or glass wool, woven into thick mats and used as insulator of heat and sound.

From Time Magazine Archive

The precaution may be taken, however, of plugging this narrow tube with a little glass wool, which renders any inconvenience from this cause quite impossible.

From Scientific American Supplement, No. 841, February 13, 1892 by Various