ENVELOPES
- ENVELOPE, a paper container [n]
- A flat paper container with a sealable flap, used to enclose a letter or document
- A covering or containing structure or layer
- The outer metal or glass housing of a vacuum tube, electric light, etc
- The structure within a balloon or nonrigid airship containing the gas
- A membrane forming the outer layer of certain viruses
- A curve joining the successive peaks of a modulated wave
- A curve or surface tangent to each of a family of curves or surfaces
- The nebulous covering of the head of a comet; coma