(1) See 
device independent pixel.
(2) (
Document 
Image 
Processing)  See 
document imaging.
(3) (
Dual 
In-line 
Package)  A common, mostly-rectangular chip housing with leads (pins) on both sides.  Tiny wires of a DIP bond the chip to metal leads that wind their way down into spider-like feet.  The DIP is either plugged into a socket or inserted into holes in the printed circuit board and soldered.  See 
DIP switch, 
CDIP, 
CERDIP and 
chip package.
The DIP
Introduced in the 1960s, the DIP package was widely used for decades and still exists to hold microcontrollers and other electronic circuits.
Lots of DIPs
Taking up more room than BGA and other chip packages that are used today, DIP chips were popular in the past.  See 
chip package.