An envelope is a container or a holding boundary. In the usual use of the term we are talking about the paper or cardboard holder and protector for a card or letter etc. We use the envelope to cover what we are sending in the mail, for privacy and to keep the letter or what have you from becoming soiled or damaged. We can also spell it as envelop, meaning to surround and or to hold in.
The fire enveloped the forest. Not exactly the same as protection from becoming soiled or damaged, is it? What this says is that the forest was consumed, subsumed, absorbed as a rock that has been tossed into the ocean, gone. A parent or grandparent can somewhat envelop a child with love and caring support. That can be taken to a length that does not let the child experience the real world. Oh oh
Envelope as protection, that is pretty typical. The envelope of error is more like a set of bounds on what is allowed or possible or expected. It gives us some comfort to be able to predict such things. We can design an envelope for a discussion, for instance. That can be helpful in preparing our talking points and in assessing the contributions from others. We can also say the envelope is the region of interest for this or that
Enveloping is surrounding to swallow up or to protect or simply to include or maybe to invade. The electoral district envelops the downtown core. The nuclear fallout enveloped everything within 100 kilometers. Is that result within or outside of the envelope? The concept of a bell shaped curve can be an envelope for data about almost anything. The gestation envelope for a butterfly is called a cocoon
“The envelope please”, a phrase that generates anticipation of something grand, the big reveal. Something elegant, sort of refined about using an envelope, don’t you think so? The use of the paper device we call an envelope peaked in about 1920. Bet you didn’t know that, huh. Its use was at a level of about five times of that in 1800. It is now used about half of that peak and use is again increasing. Who knew?