Dependent Origination means that all dhammas arise through causes or conditions. In brief, all things or phenomena arise out of mutually dependent relationship and conditions. Nothing exists without interdependent relationship and condition. Hetu and paccaya, generally speaking, are cause and condition. The Buddha defined “Dependent Origination” as follows:
          When this exists, that exists.
          Because this arises, that arises.
          When this does not exist, that does not exist.
          When this ceases, that ceases too.
These four sentences express the coexistent relationship, both simultaneous and non-simultaneous (sequential). (From Essentials of Buddhism: Questions and Answers)