Scientific and technical jargon--specialized vocabulary, usually Latinate--plays a vital role in scientific and technical communication. But its proper use continues to be a point of discussion because of our concern with audience adaptation, rhetorical exigence, rhetorical purpose, and ethics. We've focused on teaching students--and on convincing scientists, engineers, and other writers/speakers--to gear their specialized language to the recipients of their communication, to the occasion calling for their communication, to what they wish to accomplish through their communication, and to the ethical goals of safety, helpfulness, empowerment, and truth. These are exactly the sorts of things we should be doing. My contribution to this conversation is a reinforcement and, I hope, an extension of the argument that we should also be teaching and convincing students and professionals: 1) to fully appreciate what makes jargon either good or bad; 2) to carefully distinguish jargon usage from other aspects of scientific and technical style; and 3) to recognize that in every context, even in communication among experts, jargon should be used judiciously--that is, in the most helpful, least taxing way. Jargon, i.e. scientific terminology, is essential for designating new entities for which the language has no name. It makes for economy and for the accuracy and precision required in scientific research [1, p. 319]. Does the excessive use of technical terms impede the advance of science? I think it does. It kills the grace and purity of the literature by means of which the discoveries of science are made known [2, p. 116]. What if it should turn out that we are all jargon makers and jargon users, and that jargon is necessarily involved in the growth and change of language? That we are consumers of jargon as we are eaters of sliced bread? [3, p. 3]. To attempt a definition of jargon threatens unusual dangers [4, p. 69]. The above epigraphs are glimpses into discussions about both the uses of jargon and its definitions. My article enters in on such discussions, offering a point of view about the definitions and about the proper uses of jargon.