DR - Drag Racing
NN / N2O - Nitro Nation - http://www.nitronation.com
4×4 - Drag Racing 4×4 (SUV/Truck Edition)
Bikes - Drag Racing: Bike Edition
CM - Creative Mobile Games 
DRF / DRFnet - Drag Racing Forum
NNnet - Nitro Nation Forum - http://www.nitronation.net

F2F - Friend to Friend Race (online game mode)
DB - Driver Battle (online game mode)
BR / B&R - Bet & Race (online game mode)
PL - Pro League (live online game mode with upto 10 players)
PLR / Random - Pro League Random

PL1 - Pro League Level 1 (-10)
xxx rp - xxx rank points (in PL)
RP - Respect Point (premium currency in DR needed for top upgrades and cars)
HoF - Hall of Fame (5000 rank points in PL)
“Magic” HoF - HoF achieved by glitch of PL server

UPS - Upgrades
Tunes - Tuning for cars (gear ratios)
FD - Final Drive (multiplier for gear ratios)
NOS - Nitrous Oxide System. (A tuning adjustment which can be set short and powerful either, or longer with less thrust.)
PB - Personal Best (result)
WR - World Record
TO - Time Out (time out in PL)
SS - Screen Shot
DQ / disq - Disqualification

FL - Friend List
PLR - Pro League Run – Daily PL challenges announced by Pro League Run’s Facebook group
DFC - Daily Forum Challenge
DFS - Daily Forum Stock
CIH/CHI - CheatIngHacker (software for cheating used by a few racers with rooted device)

Tag *gamertag - A gamertag is a person’s online persona over different games
Tag *teamtag - A team tag is usually preceded at the beginning of gamertags as abbreviation of players team name.
FB = Facebook
VIP - Very Important Person, Very Important Player (achieved 10x HoF in levels 1-10)
MOD / Mod(s) - Moderator(s)