It is easily googled and most sites do it in such a way where it's easily understood by a layman. It would take paragraphs to try to explain it but if you are going to buy artwork, you should be familiar with the terms for sure, and honestly you can google it easier than I can compose an answer. Also look up offset printing, reproduction versus print, and glicee. Then if you don't understand it, ask specific questions.

Thank you

In a nutshell....
Engraving...made by gouging out the outline of a picture on a copper plate, spreading the plate with ink and pressing that plate onto a paper.
Etching....made in a similar manner but the image is put on the copper plate by etching it with acid.
In both cases the plate is inked and pressed onto the paper.....creating a print.
In the lithographic process, the image is drawn on a stone with a wax "crayon" and then an etching solution is applied to the stone, etching all but the area but where the image is drawn. The operating principle is that oil based ink and water based ink don't mix.
All 3 methods produce "original prints"....that is prints that are produced by the artist. Photographic reproductions...often called "prints" are different from "original prints" which are the work of the artist....not someone reproducing the artist's work.....mostly...there are exceptions.
But giclee prints are nothing more than photographic repros, as are newspaper prints, printed on an ink jet ptinter. They are not in the same realm as etchings, engravings and original lithographs.
Linda c

Thank you Linda you always take the time to teach!!

And "offset lithography" uses metal or paper plates and a rotary drum press ... it's definitely NOT handmade. It's how they make posters.

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

All you need is a good look at the unframed print and a magnifying glass. Lithos and engravings have a distinct dent around the image where the press squished the paper (this can be faked). Real engravings have visible ink lines, and you can often feel them on the paper. Real lithos have irregular inked areas - not the evenly spaced dots of a newspaper style print - especially if the print was "colored in the stone" by dabbing the colored inks onto the stone.

And don't even ASK about silkscreens!

Or wood cuts....
There are lots of ways of making an original print.
And lithographs don't have the "plate line" that indentation around the picture that etchings and engravings have.
Many old books and magazines contained original etchings and engravings in the magazine. Harper's was one who did and Godey's and Peterson's two others. The "Godey's prints" you see were once part of the magazine...but are not photographic repros.