A small, folding sleeve or case designed to hold paper currency, as well as credit cards, pictures, etc.
A paper or cardboard wrapper used to enclose small, flat items, especially letters, for mailing.
Something that envelops; a wrapping.
An enclosing structure or cover, such as a membrane; a space between two membranes
A curve that bounds another curve or set of curves, as the modulation envelope of an amplitude-modulated carrier wave in electronics.
A mathematical curve, surface, or higher-dimensional object that is the tangent to a given family of lines, curves, surfaces, or higher-dimensional objects.
The nebulous covering of the head or nucleus of a comet; a coma.
The set of limitations within which a technological system can perform safely and effectively.
The shape of a sound, which may be controlled by a synthesizer or sampler.
The information used for routing a message that is transmitted with the message but not part of its contents.
An earthwork in the form of a single parapet or a small rampart, sometimes raised in the ditch and sometimes beyond it.
A bag containing the lifting gas of a balloon or airship; fabric that encloses the gas-bags of an airship.