saliva

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The watery mixture of secretions from the salivary and oral mucous glands that lubricates chewed food, moistens the oral walls, and contains ptyalin.

Century Dictionary and Cyclopedia

1. n. Spittle; the mixed secretion of the salivary glands and of the mucous membrane of the mouth, a colorless ropy liquid which normally has an alkaline reaction. Its physiological use is to keep moist the tongue, mouth, and fauces. thus aiding the sense of taste, and to assist mastication and deglutition. Specifically, saliva is the secretion of the salivary glands, which in man and many other animals contains a digestive ferment, ptyalin. See ptyalin, and cuts under parotid and salivary.
2. n. In entomology, a neutral alkaline fluid secreted by the salivary glands when these are present, and, in their absence, by the epithelial lining of the esophagus. It has the same property as the saliva of vertebrates in transforming starchy foods into glucose.

Wiktionary

1. n. physiology A clear, slightly alkaline liquid secreted into the mouth by the salivary glands and mucous glands, consisting of water, mucin, protein, and enzymes. It moistens the mouth, lubricates ingested food, and begins the breakdown of starches.

GNU Webster's 1913

1. n. (Physiol.) The secretion from the salivary glands.

WordNet 3.0

1. n. a clear liquid secreted into the mouth by the salivary glands and mucous glands of the mouth; moistens the mouth and starts the digestion of starches