Card collectors use a lot of abbreviations! This can be confusing to new collectors but this list is here to make what you are reading just a little bit easier to understand.
RAK – Random Act of Kindness, usually gifting a card or cards
HOF – Hall of Fame
LCS – Local card store/shop
Context: buying and selling
PWE – Plain White Envelope
BMWT – Bubble Mailer with Tracking
ESE – eBay Standard Envelope
B/S/T – Buy/Sell/Trade
F&F – Friends & Family, payment method via Paypal with no purchase protection
G&S – Goods & Services, a payment method via Paypal with purchase protection
TTM – Through The Mail, usually referring to autograph requests from current or former players
OBO – Or Best Offer
ISO – In Search Of
WTB – Want To Buy
QTY – Quantity
BIN – Buy It Now
FT – For Trade
FS – For Sale
Context: card descriptions
RPA – Rookie Patch Autograph card
RC – Rookie Card
RP – Reprint
SP – Short Print
SSP – Super Short Print
USP – Ultra Short Print, the new designation for SSSP from Topps
BGS – Beckett Grading Services, a sports card grading company
PSA – Professional Sports Authenticator, a sports card grading company
PC – Personal Collection
ERR – Error Card
UER – Uncorrected Error Card, an error card that does not have a corrected version
DP – Draft Pick
NNO – No Number
NNOF – No Name On Front
OC – Off Center
ACEO – Art Card, Editions & Originals, in sports card these cards are made by artists and collectors and not the major card manufacturers
POP – Population, normally referring to how many cards exist with the same grade from the same grading company.