RSVP – Please reply. As with so much of English, this comes from French. ... ASAP – As soon as possible. ... AM/PM – Before midday (morning) and after midday (afternoon) ... LMK – Let me know. ... BRB – Be right back. ... DOB – Date of birth. ... CC/BCC – Carbon copy/blind carbon copy. ... TBA/TBC- To be announced/To be confirmed. More items...