Here's a brief introduction to those new to buying stamps on eBay. Perhaps, like myself 2 years ago, you are finding it hard to understand the terms used in philately, because really you have only collected stamps when you were a kid. Back then, pretty stamps were of the essence of collection. Whether they are mint, used, torn or whatever, it didn't really matter, yes? Yes. Well, I was a bit lost when I first started out on eBay, but I have come a long way. Here are some of the terms commonly used in stamp auctions on eBay:

MNH:
Mint Not Hinged, meaning the stamp is crisp with no flaws (unless mentioned). Not hinged means the stamp has never been hinged on sheet for display before, so its back should have full gum with no traces of hinge mark(s).
Also known as: MUH (Mint Un-Hinged), UMM (Un-Mounted Mint)

MH:
Mint Hinged, meaning the stamp is crisp with no flaws (unless mentioned). Hinged means the stamp has been hinged on sheet for display before, so its back should have traces of hinge mark(s).
Also known as: MM (Mounted Mint), MLH (Mint Lightly Hinged)

MNG:
Mint No Gum, meaning the stamp is crisp with no flaws (unless mentioned) but with no gum on the back. MNG stamps are inferior to MNH (full gum) stamps in most cases.

FU:
Fine Used, meaning the stamp has been used, but is clean and faultless, hence "fine". All perfs should be intact and there should be no creases.
Varieties: VFU (Very Fine Used)

SG:
Stanley Gibbons - a company in England specialising in collectable postage stamps. Stanley Gibbons has its own catalogue valueing most stamps, including varieties. Most stamps are catalogued as mint and used.

CV:
Catalogue Value, could be of SG's, Scott's and others.

HV:
High Values - used by sellers on eBay to attract customers.

Hope you have benefited from this, and have enjoyed reading as much as I have enjoyed writing. Happy stamping and I will be updating this guide as new ideas pop up!

Any queries, do not hesitate to contact me.