This article is from the eBay FAQ, by William B. Shaw firstname.lastname@example.org with numerous contributions by others.
Until I have some good links, here are some product acronyms I received by
amoe members. Keep in mind that many sellers aren't terribly accurate with
these descriptive terms and you should check the seller's reputation (always
good advice) before bidding.
HTF Hard To Find, or so the seller believes
MIB Mint In Box. Implies that the item is in mint condition still in it's
original box, note that this does not explicitly mean the box has never been
MIP Mint In Packet, implies that the item is in mint condition still in it's
original packet, again note that this does not explicitly mean the packet
has never been opened but implies the seal has not been broken
MOC Mint On Card, Star Wars figure etc. unopened still on it's card
MWMT Mint With Mint Tags, especially important in Beanie Babies collecting.
MWT Mint With Tag, beanies etc. that are in mint condition still with their
NIB New In Box, implies that the item is in new condition still in it's box,
the box may have been opened
NIP New In Packet, similar to MIP
NOS New Old Stock, a seller has acquired old stock that is in new condition,
i.e. it's been sitting in a warehouse for years
NRFB Never Removed From Box, implies the item has never been removed from
it's original box and the item is in mint condition
OOAK One Of A Kind, usually seen on custom-designed Barbies or other fashion
OOP Out Of Print, usually seen with books or videos
VHTF Very Hard To Find, or so the seller still believes ;)