Term of art which, when used in U.S. patent claim language, is generally accepted as meaning that only the listed elements may be present to infringe. It is thus a “closed claim.” These types of claim are rarely used, typically only in metallurgy or chemical claims, and even then usually have long lists of potential substitutes for each element. “Consisting Essentially of” is a not completely closed claim, i.e., it allows the possibility of some additional items if not “essential” to the invention. See Claims, Comprising, Closed Claim.