Endianess of architectures
The terms little-endian/big-endian is taken from an anectode from the novel Gulliver's travels. The Lilliputians were separated by those who broke their egg on the little end (becoming little-endians) and those who opened it on the big end (becoming big-endians).
|Bits||little endian||big endian|
Even though the above lists architectures either as little or big endian, some architectures are really endian-agnostic (or "bisexual"). They can be treated to act as a little or big endian CPU. PowerPC, MIPS and ARM are such CPUs. In these cases the above lists the endianess Debian uses for its GNU/Linux variant.
More information can be found here: