TWTM - The Well-Trained Mind: A Guide to Classical Education at Home
WTM-P or WTMP - Well-Trained Mind Press
WTM-A or WTMA - Well-Trained Mind Academy
WTM-LS - Well-Trained Mind Learning Services
SWB - Susan Wise Bauer
SOTW - The Story of the World
SOTW1 or SOTW-1 - the numeral indicates volume number
STOW - Nothing... but people sometimes write this instead of SOTW
and from The Story of the World Activity Books....
RA is read aloud
IR is independent reading (so is the typo "RI")
OOP is out of print
LFA is Limited Format Availability
E-Only is electronic-only (like Kindle or eBook, but not in paper-print)
HOTW - The History of the _____ World - the series
HAW - The History of the Ancient World
HMW - The History of the Medieval World
HRW - The History of the Renaissance World
OPG - The Ordinary Parent's Guide to Teaching Reading
WWE - Writing With Ease
WWS - Writing With Skill
TCW - The Creative Writer
FLL - First Language Lessons
GFTWTM or GftWTM - Grammar for the Well-Trained Mind
TGG - The Grammar Guidebook
TDD - The Diagramming Dictionary
WSW? - Who Said What?
TGS - Telling God’s Story
MFTS - Math Facts that Stick
MWC - Math with Confidence series
KMWC - Kindergarten Math With Confidence
FGMWC or FMWC - First Grade Math With Confidence
SGMWC or SMWC - Second Grade Math With Confidence
TGMWC or TMEC - Third Grade Math With Confidence
AB - Activity book (or, in context, sometimes Audiobook)
SP - Student pages
WB - Workbook
IG, IT - Instructor Guide, Instructor Text
HC - Help Center, with FAQs
USPS - United States Postal Service
UPS - United Parcel Service