MayasMama - I'm not sure which ones you know and which ones you don't, but here are some of the commonly used ones:
CD - cycle day
O - ovulate
2ww - two week wait, the time period after ovulation has been confirmed and you're waiting for your period or a positive pregnancy test
AF - aunt Flow; your period
PPAF - post partum AF; the first period after birth
OPK - ovulation predictor kit; the pee stick that detects LH
LH - luteinizing hormone, the hormone that surges right before ovulation
HCG - human chorionic gonadotropin, what a pregnancy test picks up to show that you're pregnant
HPT - home pregnancy test
FMU - full morning urine.
LP - luteal phase, the time period between ovulation and period or positive pregnancy test
LPD - luteal phase defect, when LP is less than 10 days and therefore too short for implantation of fertilized egg
Am I missing any?
Oh, and what does "CS'ing" mean? (from your siggy)