Well, yes, +1 for "uncomplicated", I just wouldn't say the term is related to complexity.
Most any software can be broken down in a modular way so that the units could be understood by a junior and you'd rarely need to think about more than one cluster of interactions at once. Maybe this is naive, but up until now found it to be true - that said, I never worked in rocket science.
(but I'm totally happy with isoprophlex's answer actually)