Complexity is a compound dimension which represents variety, frequency and amplitude of relational traits within a form.
Complex is a trait of forms which have high complexity within a specific context.
Complexity can create predictable or unpredictable conditions.
Complexity can be described as an unlimited positive dimension with the parameters of zero (for complete chaos) and infinity.
Complexity via variety can arise through a relatively small number of complex relationships; i.e., only two elements interact, but they interact quite differently depending on each element's current status and/or the context in which the interaction occurs.
Complexity can't be measured effectively except in relatively less-complex (and artificial) design contexts.