What is the definition of all existing things?

All existing things can be defined as any entities or phenomena that have a presence in reality, encompassing both physical objects and abstract concepts. This includes everything from matter and energy to thoughts, emotions, and ideas. In philosophical terms, the definition may extend to encompass the totality of existence itself, including both the observable universe and potential realities. Ultimately, it reflects the comprehensive spectrum of being and non-being within the scope of our understanding.