**Existence** refers to the state or fact of being real, present, or having actual being. It is a fundamental concept in philosophy, science, and everyday language, often relating to questions about reality, presence, and the nature of being.

### Key Definitions of Existence:
1. **General Definition**:
   - The condition of being or living in reality or fact.
   - Example: "The existence of life on Earth depends on specific environmental conditions."

2. **Philosophy**:
   - Refers to the fundamental state of being, often explored in metaphysical discussions about what it means for something to "exist."
   - Example: Philosophical debates often address the existence of abstract entities, such as numbers or moral values.

3. **Science**:
   - Concerned with proving or understanding the presence of phenomena or entities through evidence and observation.
   - Example: "The existence of black holes was confirmed through indirect observations and theoretical models."

4. **Everyday Use**:
   - Refers to one's way of life or the condition of living.
   - Example: "Their existence in the remote village was simple and peaceful."

5. **Mathematics and Logic**:
   - Refers to the property of an object or solution satisfying certain conditions.
   - Example: "The existence of a solution to the equation was proven."