  In this paper, we build a dimension theory related to Shelah's 2-rank,
dp-rank, and o-minimal dimension. We call this dimension op-dimension. We
exhibit the notion of the n-multi-order property, generalizing the order
property, and use this to create op-rank, which generalizes 2-rank. From this
we build op-dimension. We show that op-dimension bounds dp-rank, that
op-dimension is sub-additive, and op-dimension generalizes o-minimal dimension
in o-minimal theories.
