Swift.
To extract the root (Math.), to ascertain the root of a number or quantity.
Ex"tract` (?), n. 1. That which is extracted or drawn out.
2. A portion of a book or document, separately transcribed; a citation; a quotation.
3. A decoction, solution, or infusion made by drawing out from any substance that which gives it its essential and characteristic virtue; essence; as, extract of beef; extract of dandelion; also, any substance so extracted, and characteristic of that from which it is obtained; as, quinine is the most important extract of Peruvian bark.
4. (Med.) A solid preparation obtained by evaporating a solution of a drug, etc., or the fresh juice of a plant; -- distinguished from an abstract. See Abstract, n., 4.
5. (Old Chem.) A peculiar principle once erroneously supposed to form the basis of all vegetable extracts; -- called also the extractive principle. [Obs.]