Definition of "rosin" [ros•in]

• A translucent yellowish to dark brown resin derived from the stumps or sap of various pine trees and used to increase sliding friction, as on the bows of certain stringed instruments, and to manufacture a wide variety of products including varnishes, inks, linoleum, adhesives, and soldering compounds. (noun)
• To coat or rub with rosin. (verb-transitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Mr. MA: Because actually, usually rosin, which is, you know, the resin that you put on the horsehair of the bow, that friction, those little grains of resin is what makes the strings vibrate."
• "The turpentine gathered from the newly boxed or virgin tree is very valuable, on account of its producing a peculiarly clear and white rosin, which is used in the manufacture of the finer kinds of soap, and by "Rosin the Bow.""
• "Neither of the definitions given above includes the sodium and potassium salts of rosin, commonly called rosin soap, for the acid constituents of rosin have been shown to be aromatic, but in view of the analogous properties of these resinates to true soap, they are generally regarded as legitimate constituents of soap, having been used in Great Britain since 1827, and receiving legislative sanction in Holland in 1875."