Background 
Background printing 
Backlit display 
Backup 
Backup agent 
Backwards-compatible 
Bad sector 
Banner page 
Base font 
Base hardware 
Base memory or conventional memory 
BASIC 
BAT or batch file 
Battery meter 
Baud or baud rate 
Bay 
Benchmark 
Beta software 
Bezier curve 
Binary 
BIOS 
Bit 
Bitmap 
Bitmapped font 
Bits per second (bps) 
Blink 
Block 
BMP 
Book 
Bookmark 
Boot, boot up 
Boot disk 
Border 
Bounding box 
Briefcase utility 
Browsing 
Brush 
Buffer 
Bug 
Built-in 
Bullet 
Bulletin Board Service (BBS) 
Bundle 
Bureau 
Bus 
Bus master 
Button 
Byte