• Envelope (mathematics)
  Envelope (mathematics)
  In geometry, an envelope of a family of curves in the plane is a curve that is tangent to each member of the family at some point. Classically, a point on the envelope can be thought of as the intersection of two "adjacent" curves, meaning the limit of intersections of nearby curves...
  
  , a curve, surface, or higher dimensional object defined as being tangent to a given family of lines or curves (or surfaces, or higher dimensional objects, respectively)

• Viral envelope
  Viral envelope
  Many viruses have viral envelopes covering their protein capsids. The envelopes typically are derived from portions of the host cell membranes , but include some viral glycoproteins. Functionally, viral envelopes are used to help viruses enter host cells...
  
  , the membranal covering surrounding the capsid of a virus
• Cell envelope
  Cell envelope
  The cell envelope is the cell membrane and cell wall plus an outer membrane, if one is present.Most bacterial cell envelopes fall into two major categories: Gram positive and Gram negative. These are differentiated by their Gram staining characteristics....
  
   of a bacterium, consisting of the cell membrane, cell wall and outer membrane

• Envelope (waves), a curve joining the peaks of an oscillating signal, in electronics the output of an envelope detector
  Envelope detector
  An envelope detector is an electronic circuit that takes a high-frequency signal as input and provides an output which is the "envelope" of the original signal. The capacitor in the circuit stores up charge on the rising edge, and releases it slowly through the resistor when the signal falls...
  
  
• ADSR envelope, the variation of a sound over time, as is used in sound synthesis
• Envelope (mechanical engineering)
  Envelope (mechanical engineering)
  In mechanical engineering, an envelope is a solid representing all positions which may be occupied by an object during its normal range of motion.Another word for this is a "flop".-Wheel envelope:...
  
  , a solid representing all positions that an object may occupy during its normal range of motion
• Envelope (aerospace), the limits within which an aircraft can operate
• Building envelope
  Building envelope
  The building envelope is the physical separator between the interior and the exterior environments of a building. Another emerging term is "Building Enclosure". It serves as the outer shell to help maintain the indoor environment and facilitate its climate control...
  
  , the exterior layer of a building that protects it from the elements

• Envelope (band)
  Envelope (band)
  Envelope is a pop/rock band from Denmark that has been very much influenced by bands such as The Beatles. Envelope was formed in May 1998 and has to this day been actively involved in performing....
  
  , a Danish pop/rock band
• Envelopes (band)
  Envelopes (band)
  Envelopes is an indie-pop band with members hailing from Sweden and France.- History :Envelopes' debut album Demon was released in the UK in August 2005 and in America in April 2006. The album was recorded at Henrik Orrling's family farm in Sweden, where the video for their single Sister in Love...
  
  , an indie/pop band from Sweden and France, based in the UK

See also

• Two envelope problem, a paradox
• The military terms Envelopment
  Envelopment
  Envelopment is the military tactic of surrounding an enemy in the field so that they are isolated in a pocket. The friendly forces can choose to attack the pocket or invest it and wait for a beleaguered enemy to surrender.To achieve an envelopment several different tactics can be employed:* A...
  
   and envelop