Pizza-box form factor
In computing, a pizza box is a style of case for computers. It tends to be very thin, normally 1U to 2U in height, and wide and flat. The result is a case that looks like the boxes used to deliver pizza, and thus the name.
The first computers generally referred to as pizza box machines were early Sun Microsystems desktop workstations. Other famous examples include the NeXT Computer NeXTstation and Apple Computer's Macintosh LC.
The pizza box style has since fallen from use in desktop computers, as standards have forced the tower and minitower designs into the fore. However, the fact that pizza boxes can be neatly stacked on a rack has made them the most popular casing for the powerful computers typically deployed in data centers.
