[{"Bold_text": "noun", "List Items": ["a flat paper container, as for a letter or thin package, usually having a gummed flap or other means of closure.", "something that envelops; a wrapper, integument, or surrounding cover.", "Biology.a surrounding or enclosing structure, as a corolla or an outer membrane.", "Geometry.a curve or surface tangent to each member of a set of curves or surfaces.", "Radio.(of a modulated carrier wave) a curve connecting the peaks of a graph of the instantaneous value of the electric or magnetic component of the carrier wave as a function of time.", "the fabric structure enclosing the gasbag of an aerostat.", "the gasbag itself.", "Electronics.the airtight glass or metal housing of a vacuum tube.", "the technical limits within which an aircraft or electronic system may be safely operated."]}]