flat
flat: adj. 1. [common] Lacking any complex internal structure.
"That bitty box has only a flat filesystem, not a hierarchical
one." The verb form is flatten. 2. Said of a memory architecture
(like that of the VAX or 680x0) that is one big linear address space
(typically with each possible value of a processor register
corresponding to a unique core address), as opposed to a `segmented'
architecture (like that of the 80x86) in which addresses are
composed from a base-register/offset pair (segmented designs are
generally considered cretinous).
Note that sense 1 (at least with respect to filesystems) is usually
used pejoratively, while sense 2 is a Good Thing.