This glossary was compiled by Don B at jaguarforums.com and is reproduced here
with his permission

TA = Traffic Announcements
Tab Washer = Flat washer with projecting tab that is bent upward to lock against the nut or bolt head
Tach or TACH = Tachometer, Rev Counter, revolution counter
Tachometer = Rev Counter, revolution counter, Tach or TACH
Tappet = A sliding rod or capped cylinder intermittently struck by a camshaft lobe to open a valve.
Tata Motors = Mumbai, India-based corporate owner of JLR since 2008
Tata, Ratan = Former Chairman of Tata Motors who oversaw the acquisition of JLR from Ford
TAU = Theft Alarm Unit
TAVDICT = Torque Actuated Variable Dual Independent Camshaft Timing (See VCT, VVT)
TB = Throttle Body
TC = Torque Converter; Turbocharger/Turbocharged engine; Top Center (TDC); Traction Control
TCC = Torque Converter Clutch
TCM = Transmission Control Module
TCMISO = Transmission Control Module ISO bus
TCS = Traction Control System
TDC = Top Dead Center, Top Center (TC)
Teflon = DuPont trademark for polytetrafluroethylene (PTFE) class of thermoplastics
TFT = Thin-Film Transistor, Transmission Fluid Temperature Sensor
TFT LCD = Thin-Film Transistor Liquid Crystal Display
TFTS = Transmission Fluid Temperature Sensor
Thermistor = Temperature-sensitive resistor
Throwout Bearing = Thrust Bearing
Thrust Bearing = Throwout Bearing
Tick Over = Idle, or the engine speed at tick over
Tie Rod = Track rod, connecting rod (steering)
Tie Rod End = Track rod end (steering)
Tire = Tyre
TFT = Transmission Fluid Temperature Sensor
TM = Throttle Motor
Toll Motorway = Turnpike
Tonneau = Tonneau Cover A waterproof cover fastened over the cockpit of a roadster or convertible
Toothed Lock Washer = Internal or External Teeth, Shakeproof Washer, Star Washer (External Teeth)
TOPix = JLR Technical and Owner Publications Information Exchange (formerly GTR)
Top Dead Center = Position of piston when it is at its farthest distance from the crankshaft (see BDC)
Torch = Flashlight
Torque = Rotational force, measured in pound-feet (lb-ft) or Newton-meters (Nm)
Torque & Torque Pro = Android OBDII app that pairs with a Bluetooth device such as an ELM327
Torque Converter = Fluid coupling that replaces a mechanical clutch in an automatic transmission.
Torsion Bar = Anti-sway bar, anti-roll bar, stabilizer bar, sway bar
Torx = “Star” fastener, trademarked screw head design with 6 internal or external lobes or points; 6lobe
Torx Plus = Improved head profile Torx fastener
Torx, Security = Torx screw with a pin centered in the internal lobe socket requiring a special bit
TOT = Transmission Oil Temperature
TP = Throttle Position, Throttle Position Sensor (TPS), Throttle Potentiometer (TPP)
TP = radio Traffic Program
TP1 = Throttle Position Sensor Resistive Element 1
TP2 = Throttle Position Sensor Resistive Element 2
TPM = Tire Pressure Monitoring System
TPMS = Tire Pressure Monitoring System or Sensor
TPP = Throttle Potentiomenter, Throttle Position Sensor (TPS)
TPS = Throttle Position Sensor (potentiometer) (TP), Throttle Position Switch (On/Off only)
TQ = Torque (TRQ)
Track Rod = Tie rod, connecting rod (steering)
Track Rod End = Tie rod end, Connecting rod end (steering)
Trannie = Transmission, Trans, Gearbox, Box
Tranny = Transmission (Gearbox)
Trans = Transmission, Trannie, Gearbox, Box
Transaxle = Combination transmission & axle drive for front-wheel and all-wheel drive systems
Transducer = Converts one form of energy to another, e.g. pressure to electricity; electricity to sound
Transfer Box = Transfer Case, additional gear set for AWD and 4WD vehicles
Transfer Case = Transfer Box, additional gear set for AWD and 4WD vehicles
Transmission = Gearbox, Trans, Trannie, Box
Transponder = Passive security device in the key or fob of a PATS-equipped vehicle
Tread Plate = Sill plate, sill finisher
Trigger Wheel = Reluctor, sensor ring, sensor rotor
TRQ = Torque (TQ)
TS = Throttle Switch
Trunnion = Cylindrical device fitted to a throttle cable, choke cable, etc. to serve as a stop
Truck = Lorry
Trumpet = Bell- or horn-shaped section of a carburetor or throttle body inlet, warning horn output, etc.
TS = Twin Screw (a type of supercharger)
TSB = Technical Service Bulletin, updated information from Jaguar to Dealers & Technicians (JTB)
Tuffelt = Thick underfelt fabric used for sound-deadening and padding in Jaguar interiors
TURN = Turn Signal
Turn Signals = Indicators, Direction Indicators, Signals (DI)
Turnpike = Toll Motorway
TV = Television
TVbB or TVBB = Torque Vectoring by Braking
Twin Cam = Dual- or Double-Cam engine, typically a DOHC engine
Twin OHC = Dual- or Double-Cam engine, typically a DOHC engine
TWR = Tom Walkinshaw Racing, partner in JaguarSport and TWR special edition models (see TRW)
Tyre = Tire