talcs

Noun

talc (countable and uncountable, plural talcs)

1. (obsolete) Originally a large range of transparent or glistening foliated minerals. Examples include mica, selenite and the hydrated magnesium silicate that the term talc generally has referred to in modern times (see below). Also an item made of such a mineral and depending for its function on the special nature of the mineral (see next). Medieval writers adopted the term from the Arabic.
2. (obsolete) A microscope slide made of a plate of mica, generally in use from the start of modern microscopy until the early nineteenth century, after which glass slides became the standard medium.
   • M. [Antonie van] Leeuwenhoek fixed his objects, if they were ſolid, to the foregoing point with glue; if they were fluid, he fitted them on a little plate of talc, or exceeding thin blown glaſs, which he afterwards glued to the needle, in the ſame manner as his other objects.1787, George Adams, Essays on the Microscope; containing a Practical Description of the most Improved Microscopes: a General History of Insects, their Transformations, Peculiar Habits, and Œconomy...
3. A soft mineral, composed of hydrated magnesium silicate, that has a soapy feel and a greenish, whitish, or grayish color, and usually occurs in foliated masses.
   • The abeer is often mixed with powdered talc to make it glitter, and then, if it gets into the eyes, it causes a good deal of pain.1856, Life in Brazil, page 103
4. Talcum powder.

See all 5 meanings of talc