talc

Etymology

From Middle French talc, from Arabic طَلْق (ṭalq), from Persian تلک (talk).

noun

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). Mediaeval 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: an Account of the Various Species and Singular Properties of the Hydræ and Vorticellæ: a Description of Three Hundred and Seventy-nine Animalcula; with a Concise Catalogue of Interesting Objects: a View of the Organization of Timber, and the Configuration of Salts when under the Microscope, London: Printed for the author, by Robert Hindmarsh, Printer to His Royal Highness the Prince of Wales, No. 32, Clerkenwell-Close; and sold by the author, at his Shop, Tycho Brahe's Head, No. 60, Fleet-Street, →OCLC, page 7
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.
   With this background and experience we feel justified in stating that not all talcs contain, or are associated with, asbestos. 1978, C. J. Parmentier, G. J. Gill, “Practical Aspects of Talc and Asbestos”, in C. C. Gravatt, Philip D. LaFleur, Kurt F. J. Heinrich, editors, Proceedings of Workshop on Asbestos, Definitions and Measurement Methods, page 406
   For example, Montana talcs approximate the theoretical composition, while California talcs often contain calcite (CaCO₃) and dolomite (CaCO₃ • MgCO₃). 1987, Joseph A. Radosta, Nikhil C. Trivedi, “Talc”, in H. S. Katz, J. V. Mileski, editors, Handbook of Fillers For Plastics, page 217
   Micronized talcs and, to an even higher degree, submicrometer talcs significantly influence the processing parameters. 2003, Harutun Karian, Handbook of Polypropylene and Polypropylene Composites, revised & expanded edition, page 573
4. Talcum powder.

verb

1. (transitive) To apply talc to.
   "Generous talcing" is applied not only to the naked bale, but to the inside of the wrapper, and after stenciling, to the interior of the package. This talcing is repeated, "if necessary, dependent upon the number of handlings up to and into stores for steamer loading." 1940, Rubber Journal, volume 99, page 479
   Three manufacturers have now produced separate designs for talcing boxes; one uses conventional techniques of brushing and vibrators, one is a fluidised bed and the third is an electrostatic applicator. 1977, Great Britain Health, Safety Executive, Manufacturing & Service Industries, page 43
   Then he talced his hands, slipped on a new pair of rubber gloves, went to the shapeless thing at the other end of the table, and began to work. 1983, Aaron Elkins, The Dark Place, published 2010, page 107