Asbestus

Mineralogy. a fibrous mineral, either amphibole or chrysotile, formerly used for making incombustible or fireproof articles.
a fabric woven from asbestos fibers, formerly used for theater curtains, firefighters’ gloves, etc.
Theater. a fireproof curtain.
Historical Examples

It consisted of a tube, containing at one end a plug of asbestus, moistened with a solution of iodide of potassium and starch.
The Edinburgh New Philosophical Journal, Vol. XLIX Various

There was a city of the same name in Eubœa, expressed Carystus, where the stone asbestus was found.
A New System; or, an Analysis of Antient Mythology. Volume I. Jacob Bryant

Stones also differ in their weight or gravity: for instance, some of the asbestus kind are lighter than water.
A Catechism of Familiar Things; Their History, and the Events Which Led to Their Discovery Benziger Brothers

The asbestus, a mineral substance of a whitish or silver color.
A Catechism of Familiar Things; Their History, and the Events Which Led to Their Discovery Benziger Brothers

noun

any of the fibrous amphibole and serpentine minerals, esp chrysotile and tremolite, that are incombustible and resistant to chemicals. It was formerly widely used in the form of fabric or board as a heat-resistant structural material
(as modifier): asbestos matting

n.

1650s, earlier albeston, abestus (c.1100), name of a fabulous stone, which, set afire, could not be extinguished; from Old French abeste, abestos, from Latin asbestos “quicklime” (which “burns” when cold water is poured on it), from Greek asbestos, literally “inextinguishable,” from a- “not” (see a- (3)) + sbestos, verbal adjective from sbennynai “to quench,” from PIE root *(s)gwes- “to quench, extinguish” (cf. Lithuanian gestu “to go out,” Old Church Slavonic gaso, Hittite kishtari “is being put out”).

The Greek word was used by Dioscorides as a noun meaning “quicklime.” “Erroneously applied by Pliny to an incombustible fibre, which he believed to be vegetable, but which was really the amiantos of the Greeks” [OED]. Meaning “mineral capable of being woven into incombustible fabric” is from c.1600 in English; earlier this was called amiant (early 15c.), from Latin amiantus, from Greek amiantos, literally “undefiled” (so called because it showed no mark or stain when thrown into fire). Supposed in the Middle Ages to be salamanders’ wool. Prester John, the Emperor of India, and Pope Alexander III were said to have had robes or tunics made of it.

asbestos as·bes·tos or as·bes·tus (ās-běs’təs, āz-)
n.
Either of two incombustible, chemical-resistant, fibrous mineral forms of impure magnesium silicate, used for fireproofing, electrical insulation, brake linings, and chemical filters. adj.
Of, made of, or containing one or the other of these two mineral forms.
asbestos
(ās-běs’təs)
Any of several fibrous mineral forms of magnesium silicate. Asbestos is resistant to heat, flames, and chemical action. Some forms have been shown to cause lung diseases. For this reason, asbestos is no longer used to make insulation, fireproofing material, and brake linings.