The Anatomy of an Envelope – Envelope 101

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Anatomy of an Envelope

Have you ever stopped to look at the intricate anatomy of an envelope? It is more than just a folded and glued piece of paper but is a product of simplistic innovation that often gets overlooked but is incredibly useful. An envelope has been engineered with a lot of thought and user function in mind. We know this because our WCP Envelope team has been manufacturing, converting, and printing envelopes since the mid-1980s.

The Nine Parts of an Envelope

  1. Seal Flap: The seal flap is at the top of an envelope. It is the part you fold down to seal it and use to open it.
  2. Gum Seal: The gum seal is a liquid-activated adhesive on the seal flap that keeps the envelope secure before opening.
  3. Shoulder: The shoulder is considered the top edges of the bottom flap and side flaps when folded together to create the opening of the envelope.
  4. Throat: The throat is where the contents get inserted into the envelope.
  5. Side Flaps: Side flaps are folded and then sealed to the bottom flap to secure to the bottom. They are sealed together with a stronger adhesive than the gum seal since they are not intended to be separated.
  6. Face: The front of the envelope is called the Face. If you are sending the envelope through the mail it is the side where you would place the postage stamp, receiving address, and returning address. Depending on the type of envelope, this is usually the side where a window would be installed.
  7. Bottom Flap: The bottom flap is what gets folded over the side flaps to create the bottom closure of the envelope.
  8. Side Fold: The side fold is created when the side flaps are folded to the bottom flap.
  9. Bottom Fold: The bottom fold is the fold made by the bottom flap after it has been adhered to the side flaps.

Diagram displaying envelope anatomy and components

Want to learn more about Envelopes?

For more information about envelopes, check out our other blog posts such as What’s the Difference Between Diagonal Seam and Side Seam Envelopes and Paper 101: Envelope Types. For a better side-by-side comparison of different types of envelopes, our new US Office Envelope Guide is a great resource. It has envelopes ranging from commercial envelopes, coin envelopes, magazine envelopes, and more. 

Our Account Managers and WCP team can help find the right envelope solution for your business needs. To learn more, contact your local WCP sales and customer service team, we’d be happy to set up a consultation to discuss what type of envelopes will suit the needs of your business best. Give us a call today at (877) 398-3030.

Did You Know? Our WCPE Team converts envelopes of all sizes, shapes, and paper stocks. We have steel rule and adjustable die cutting, which allows us to create envelopes that will truly impress your most demanding clients. With WCP Envelope as your envelope manufacturer, you can deliver the envelopes that you envision with superior quality, timeliness, value, and consistency.