Saliva. saliva. (Science: physiology) The secretion from the salivary glands. In man the saliva is a more or less turbid and slighty viscid fluid, generally of an alkaline reaction, and is secreted by the parotid, submaxillary, and sublingual glands.In the mouth the saliva is mixed with the secretion from the buccal glands. 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.A thick transparent liquid rich in digestive [[enzymes like [[amylase, used to break down foodstuff.