Tab 
Tab key 
Tab rack or ruler line 
Tab stops 
Tabbing order 
Table of contents 
Taskbar 
TCP/IP 
Technical support 
Telecommuting 
Teleconferencing 
Template 
Terminal 
Terminate and stay resident (TSR) 
Terminator 
Text file 
Texture mapping 
TFT screen 
Thesaurus 
Thin film transistor 
32-bit system 
Thrashing 
Threshold 
Thumbnail 
TIFF 
Tile 
Title bar 
Toner 
Toner cartridge 
Toolbar 
ToolTips 
Touch pad 
Touch screen 
Tracing 
Track 
Trackball 
Transputer 
Tree of folders 
TrueType 
TSR 
Tweening 
Type size 
Type style 
Typeface