An imbalance is any occasion where balance is not occurring. This is used in cases where the balance is of some elements or quality rather than something tipping over. When something falls over that thing has been unbalanced. Imbalances typically occur continually. For instance soil can have a pH imbalance which can hurt plant growth. This can be corrected by adding more acid or alkali to move pH to the desired level. Balance is a funny word. The core meaning is about centers of mass and things falling over but it can be applied to anything where there is a desired point on any sort of dimension. Chemical imbalances in the brain cause mental illness. This is an enormous oversimplification of biochemistry which fails to capture the overwhelming complexity of brain function while being technically correct about certain conditions being related to the excess or lack of neurotransmitters. Imbalances in cash flow are only a problem in one direction while imbalances in mathematical equations are always wrong.
The above examples illustrate that the word imbalance is used in a number of fashions. All of them refer to the concept of there being some range that should be avoided but beyond that it's fairly loose. The origin of the word balance is scales and reflects how a simple tools operation creates a concept with startling reach. Cosmic imbalance is one of those ideas that doesn't actually refer to any particular state of the world and yet it has visceral pull. The notion that there is a right state for the world to be in and that actions can be taken to move it back to that right state is powerful and whole civilizations rise and fall according to the maintenance of that state. That may seem like a superstition but if you have the choice of living in a pious society where people honor their oaths and one where you can expect to get cheated at every turn you might change your tune. All of this and so much more from a tilting tool of commerce and comparison.
IRON NODER XVII: ALL'S FERROUS IN LOVE AND NODING