ATX

From PC Jargon Dictionary
This page is still missing content. Editor's may want to add to it.
ATX motherboard size comparison; rear is on left.
  FlexATX (229 × 191 mm)
  microATX (244 × 244 mm)
  Mini ATX (284 × 208 mm)
  ATX (305 × 244 mm)
  Extended ATX (EATX) (305 × 330 mm)
  WTX (form factor) (356 × 425 mm)

ATX is the most well known motherboard form factor, at 305 x 244mm. (12 x 9.6in)