cochineal

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A red dye made of the dried and pulverized bodies of female cochineal insects. It is used as a biological stain and as an indicator in acid-base titrations.
2. n. A vivid red.

Century Dictionary and Cyclopedia

1. n. A dyestuff consisting of the dried bodies of a species of insects, the Coccus cacti, found upon several species of Opuntia and other Cactaceæ, especially O. Tuna, O. Ficus-Indica, and Nopalea cochinillifera. It colors a brilliant crimson, which is changed by acids to an orange-red and by alkalis to violet; a brilliant scarlet dye is prepared from it. The cacti upon which the insect lives, bearing the general name of nopal, are extensively cultivated as food for them in the tropical countries of America, and in Java, Algeria, etc. The females only are valuable for their color, and are collected twice a year, after they have been fecundated and have laid eggs sufficient for a new brood. They are killed by spreading them upon heated plates, by putting them in ovens, or by immersing them in boiling water or exposing them to its vapor. Those killed by heated plates are of a blackish color, and are considered to be the finest; they are called zacatilla. Those from ovens are next in value; they are of an ash-gray (blanco or silver-white) color, and are called silver cochineal, or jaspeada. Those killed by water or vapor are of a reddish-brown color, and are the least valuable. The fragments, dust, and impurities from cochineal are collected and used as an adulterant, under the name of granilla. The finest grade often goes by the name of mestica or mesteque, and is exported in large quantities from Honduras. Besides the finer grades, which are cultivated insects, a considerable trade is carried on in inferior or wild insects; they are scarcely more than half the size of the cultivated species, and are covered with a cottony down which adds a useless bulk. Good cochineal has the appearance of small, deep brown-red, somewhat purplish grains, wrinkled across the back with parallel furrows, intersected in the middle by a longitudinal one. The coloring principle obtained from cochineal is carminic acid. (See carmine, 3.) East Indian cochineals, so called, are smooth glistening black grains, of no value; they are used to adulterate the genuine, which are easily distinguishable from them.
2. n. The insect which produces the dyestuff known by the same name. See def. 1.

Wiktionary

1. n. A species of insect (Dactylopius coccus).
2. n. A vivid red dye made from the bodies of cochineal insects.

GNU Webster's 1913

1. A dyestuff consisting of the dried bodies of females of the Coccus cacti, an insect native in Mexico, Central America, etc., and found on several species of cactus, esp. Opuntia cochinellifera.

WordNet 3.0

1. n. a red dyestuff consisting of dried bodies of female cochineal insects
2. n. Mexican red scale insect that feeds on cacti; the source of a red dye