separation
The state of people or things being apart from each other.
Separation means moving apart or being kept apart from someone or something. When your parents drop you off at summer camp, that separation might feel difficult at first, but most kids adjust and have a great time. When a friend moves to another city, the physical separation doesn't have to end your friendship, though you'll need to work harder to stay connected through letters, video calls, or visits.
Separation can describe physical distance, like the separation between Earth and Mars, or divisions between things that need to stay apart. In recycling, we practice waste separation by sorting plastic, paper, and glass into different bins. Scientists use separation techniques to divide mixtures into their individual parts, like separating salt from water by evaporation.
The word also describes formal splits or endings. The separation of church and state is a principle in American government meaning religious institutions and government institutions remain independent. When a married couple grows apart, they might go through a legal separation before deciding whether to divorce. In chemistry, a separatory funnel lets scientists separate liquids that don't mix, like oil and water.
Notice that separation isn't always permanent or negative. Sometimes things need to be separated for good reasons, like keeping raw meat separate from vegetables to prevent contamination, or maintaining some separation between work time and free time.