K.M.
Seriously Mamapeidea, can we have a FAQ on abbreviations... in addition you CAN google them but here is a quickie.
"D" tyipcally means dear before a family Member ie DD dear daughter
SS would mean Step Son, SD, SM, SF would fall in line
LO Little One
MIL Mother In Law, SIL, BIL, FIL etc
Honestly, I just look up the ones I do not know then ask if needed.