Word Choice: Envelope vs. Envelop

Almost everyone uses email these days, bypassing the need to write on paper and then send that piece of paper to its recipient enclosed within another piece of paper. But there are three reasons you still need to know how to spell the word ‘envelope’ correctly:

1. ‘Envelope’ has more than one use, making it vital terminology in some fields
2. ‘Envelope’ is easily confused with ‘envelop’, but each has a distinct meaning
3. Because you want to impress people like us (i.e. pedantic proofreader types)

All of these are utterly valid motivations for distinguishing between ‘envelope’ and ‘envelop’, especially the third one, so pay close attention to the following information…

Envelope (A Paper Container)

The principal meaning of ‘envelope’, as implied above, is the flat, paper container used for sending letters and other thin packages:

I put the form in the envelope, but it must have got lost in the post!

You might have known that already, but ‘envelope’ has technical senses that might be less familiar, including:

• In biology, an envelope is the membrane or outer layer of bacteria and viruses
• In geometry, an envelope is a curve tangential to every member of a set of curves
• In physics, an envelope is a curve describing the highs and lows of an oscillating signal
• In aeronautics, a flight envelope describes the limits within which an aircraft is stable

Interestingly, despite being quite technical, this final definition of ‘envelope’ is where we get the common phrase ‘pushing the envelope’, since it refers to test pilots ‘pushing’ the flight envelope of experimental aircraft!

Envelop (Wrap or Enclose)

The verb ‘envelop’ refers to the action of wrapping or enclosing something within something else:

Enveloped in protective clothing, Harold tended to the beehive.

On the Scottish moors, the enveloping fog makes it difficult to see far.

In every case, however, ‘envelop’ refers to covering, surrounding or enclosing something.

Envelope or Envelop?

The confusion between these words is understandable, since an ‘envelope’ is designed to ‘envelop’ a letter or package. But the ‘e’ at the end of ‘envelope’ is important if you want your work to be free from errors.

The easiest way to remember the difference is to keep in mind that ‘envelope’ is always a noun (i.e. a thing), whereas ‘envelop’ is a verb (i.e. an action):

Envelope (noun) = A paper container for letters

Envelop (verb) = To cover or enclose

And if you’re ever unsure about how to use a word, you can always get your work proofread!