Causality as @glebovg states is a very basic understanding of the relation between two objects and the event which takes place based on the interaction. Because you have posted in Philosophy channel i am not sure you do not want the deterministic answer.
Personally i think the more interesting area of causality is found in Psychology
"investigating how people and non-human animals detect or infer causation from sensory information, prior experience and innate knowledge."
http://en.wikipedia.org/wiki/Causality#Counterfactual_theories
Aristotle started it all with the 4 causes. The material cause,the formal cause,the efficient cause and the final cause
This leads down a very interesting rabbit hole in the synchronicity of consciousness and the collective interactions of humans. What is priority in cause. For instance, we all make decisions in our lives and a lot of decisions we know will have a major effect negative or positive. Yet some actions seem minor yet they too have major consequential effects. These effects are all interlaced with and determined in priority to connections we have made to other objects ( living or non living - as is our current understanding in our collective attribution to the warming of this planet, yet we all as a collective continue even in the knowledge of our destructive nature ). This can then lead to perception illusions and the drawings of MC Escher ... if you let it. Mergers into a fringe science, which is always more interesting it seems.
http://www.youaretrulyloved.com/enlightenment/the-illusion-of-causality/
Tie these ideas on a time spectrum and dare to introduce the uncertainty principle. This like LSD for people who like to learn.
You however did ask the question in a very deterministic manner, and if you are looking for the scientific interpretation you might want to try the Physics channel http://physics.stackexchange.com