1. Lacking any complex internal structure. "That bitty box
has only a flat file system, not a hierarchical one." The verb
form is flatten. Usually used pejoratively (at least with
respect to file systems).
2. Said of a memory architecture like that of the VAX or
Motorola 680x0 that is one big linear address space
(typically with each possible value of a processor register
corresponding to a unique address). This is a Good Thing.
The opposite is a "segmented" architecture like that of the
Intel 80x86 in which addresses are composed from a
base-register/offset pair. Segmented designs are generally
considered cretinous.
3. A flat domain is one where all elements except bottom
are incomparable (equally well defined). E.g. the integers.
