What's faces by which a solid figure is named?

I'm not sure what you are asking here:
"What's faces by which a solid figure is named?"
Could you try phrasing it a different way?  perhaps with examples?

The higher regular solids are named by the number of flat surfaces out of which they are made.

but some hexahedrons are more commonly known as cubes..

are you asking for the meaning of the word "face"?
http://mathwords.com/f/face_of_a_polyhedron.htm

since he wrote it's a 5th grade math:

I think you are asking about conic shapes:

http://en.wikipedia.org/wiki/Conic_section

parabola , circle , ellipse , hyperbola.
in the picture, 2 crossections are missing : "dot and line"

This is a 5th Grade crossword puzzel on solid shapes.  I myself don't know what they are asking.  The information I have is as follows:

"Faces by which solid figure is named".  The answer is five letters and third letter letter is an 's'.

Maybe I should rescind this question.  

>> "Faces by which solid figure is named"

Is this a translation ? Or is this literal English ?

use bases then and see if it works out.  That word is at least close enough for crossword puzzle use.

literal English

>> literal English

I was asking because "Faces by which solid figure is named" doesn't make a lot of sense to me (with the caveat that I'm not a native English speaker).

I'm trying to find an interpretation of that phrase that makes sense.
A pyramid could be named for its base: square pyramid, pentagonal pyramid, ...
but if that's what was meant, it's such an awkward way to say that it seems very confusing, especially for fifth graders.

That's a stretch, but you're probably right ... Nice detective work ;)

Amazing work.  Expert was persistent at providing solution to a poor described question.

It is very sad to see fifth graders taught rote pattern matching instead of understanding.

All your base are belong to us.

heh ... Too true :)