[ en-vuh-lohp, ahn- ]
See synonyms for: envelopeenvelopes on Thesaurus.com

  1. a flat paper container, as for a letter or thin package, usually having a gummed flap or other means of closure.

  2. something that envelops; a wrapper, integument, or surrounding cover.

  1. Biology. a surrounding or enclosing structure, as a corolla or an outer membrane.

  2. Geometry. a curve or surface tangent to each member of a set of curves or surfaces.

  3. 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.

  4. the fabric structure enclosing the gasbag of an aerostat.

  5. the gasbag itself.

  6. Electronics. the airtight glass or metal housing of a vacuum tube.

  7. the technical limits within which an aircraft or electronic system may be safely operated.

Idioms about envelope

  1. push the envelope, to stretch established limits, as in technological advance or social innovation.

Origin of envelope

1700–10; <French enveloppe, derivative of envelopper to envelop

Words that may be confused with envelope

Words Nearby envelope

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use envelope in a sentence

British Dictionary definitions for envelope


/ (ˈɛnvəˌləʊp, ˈɒn-) /

  1. a flat covering of paper, usually rectangular in shape and with a flap that can be folded over and sealed, used to enclose a letter, etc

  2. any covering or wrapper

  1. biology any enclosing structure, such as a membrane, shell, or skin

  2. the bag enclosing the gas in a balloon

  3. maths a curve or surface that is tangent to each one of a group of curves or surfaces

  4. electronics the sealed glass or metal housing of a valve, electric light, etc

  5. telecomm the outer shape of a modulated wave, formed by the peaks of successive cycles of the carrier wave

  6. push the envelope informal to push the boundaries of what is possible

Origin of envelope

C18: from French enveloppe, from envelopper to wrap around; see envelop; sense 8 from aeronautics jargon, referring to graphs of aircraft performance

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012