Recently I Was Trying To Explain Blender To My Family Who Know Absolutley Nothing About Blender Or 3D And Eventually I Gave Up But I Was Curious To See What Other People Might Say If They Were Put In This Position.
So How Would You Explain Blender To Someone Who Has Never Heard Of It?
I’d relate it to something they know, will have seen, or heard of. If I want them to have a positive reaction to what I am doing, I pick things they have positive feelings about.
If they’re at least plugged somewhat into popular culture, I’ll enthuse like: Blender is the kind of computer program one can use to create a wide variety of imagery, from the entirely imaginary to the realistic – and one can make the imaginary look realistic if one wants. For example one can build a model of somebody’s house inside the computer and show them how their new Ikea furniture would look. One can make images to illustrate what life on Mars might be like. One can make video game art. Create flying logos for TV stations. Show off a new product design in the best light before the product actually exists. Make special effects and fantastical creatures like in Harry Potter. Draw and animate cartoons like South Park, animate movies like Toy Story, create spaceships and aliens for science fiction movies like Star Wars. ^takes a breath^ any questions? 
If they’re completely disconnected from what computer technology can do by now I might reduce it all the way down to “I create pictures, but instead of using traditional methods like paint and brushes on canvas I do it with computer programs – wanna see?”
Depends on what you want to achieve by the end of conversation.
I tend to randomly talk about whatever problem I’m stuck at (whether anyone wants to hear or not 
). Pointing at surfaces to explain normal maps, waving hands to show vectors or bone influence, bending random things to demonstrate deformations… that sort of stuff. Most of the terms are not usually translated to my native language anyway, so I try to avoid them and explain what things do and mean.
This sort of information accumulates over time.
It also helps to show your work in progress. “Hey look, I rigged that thing I was working on, it can do a silly dance now, he-he. And see legs stick to the floor? That’s what IK is doing…”
At the very least, with time others can get a feel for what is difficult for you to do and what is easy, and won’t treat Blender (or any app) as magic “make-it-beautiful” button.
Of course, my family are all old gamers, so there was always some basic understanding of 3D art that comes with it and willingness to see past the illusions.
I’d pick up a pencil and make it in Blender and say, “Look, it’s on the other side of my computer screen, isn’t that awesome!?”
Usually the object is too complex and I give up just by looking at it, or I don’t have people who are interested enough, but that’s what I’d do!
I am used to that exercise.
I start to explain what it does :
It is a software that contains everything to create 3D animated movies.
But you can use it to accomplish less complicated goals. So, it has a large range of uses.
Illustrations, 3D assets and 3D scenes for video games, simulations, VR , 3D models for 3D printing, VFX, 2D animated movies…
At that moment, technical people evoke CAD software, they learned in school.
Then, I explain its accessibility :
It is a free open source software under GPL license.
So, it is free and users are free to use it for any purpose.
Anybody is free to contribute to its development, to modify it and share it, modified or as is.
At this point, job is done. But often, you have to explain that is founded by Blender Foundation through development fund and blender cloud. Or you have to detail a little bit, GPL license or Blender’s history.
Or discussion goes on how wide is Blender community, famous productions done with Blender, open movies.
“it’s a box that makes magic, but sometimes fails to find solution for one or more bones”
Why would you want to? And do they really want to know? Maybe they’ll just see you as obsessing over a childish interest. That’s what most of my siblings would think.
Arthur C Clarke :
Any sufficiently advanced technology is indistinguishable from magic
Maybe start with some good old trigonometry…
with math it’s possible to describe a circle and a triangle,and more and if you but them together you got something like well a smiley face… and so this sofftware can use this also to make this
( → preassembled blend file to show 
)
…or even this…
( → show a dino… 
even better a walking one) …
Um, it’s complicated…
Mouse, Keyboard, YouTube, Swearing
…a looooooooot of swearing
Simple!
It’s the one that blends pixels not foodstuff - mic drop
“You know Pixar movies? And you know special effects in films and those kind of things? And you know videogames? Blender is a software that allows you to create all that and other things too. It is created as free software, meaning everyone can contribute to it and it is free forever.”
When explaining 3d, it is objectively difficult to make sense of those things to people who are not familiar with them. Referring to finished products, such as 3d movies, or video games, or vfx, or archviz, or whatever, is a good way to make them immediately understand. It is a simplification, but it’s the best way to give a generic sense of what one is doing to people.
The usual suspect will answer:
But those are only animated cartoons… they are drawn on paper…
What’s that? They aren’t real?
But that aren’t computers. There is a reason why they are called consoles. Next you will tell my my phone is a computer…ha…
To @sacboi : Yes you can make art by putting of the lit on a blender… all over the kitchen ceiling and more after it drops down 
in color and in 3D 
To this regard, on the opposite, many people often (and unfortunately) have very strong negative opinions about VFX 
I believe the conversation could possibly become a rant about how much VFX suck and how they have ruined cinema
touché…rofl