separation is the act or process of setting things apart, or the state of being apart — and, by extension, the point, line, or gap that divides one thing from another.
The word reached English around 1400 from Old French separacion and Latin separationem, from separare, "to pull apart," built from se- ("apart") and parare ("to make ready, prepare"). Its senses run from the physical — sorting a mixture into its parts, the space between two objects — to the social and legal: since about 1600 it has also named spouses living apart by agreement or decree without ending the marriage. In every sense the word points at the division itself rather than at either side of it.
Separation is not distinction, which marks a difference without implying distance, and it is not isolation, which names the condition of being cut off and alone. It sits nearer to division and detachment, but carries a stronger suggestion of something once joined that is now held apart.
In philosophy and ecological thought the word has taken on a larger meaning. 📝Charles Eisenstein uses it in 📝The Ascent of Humanity for the worldview of the 📝separate self — the individual experienced as fundamentally divided from nature, from other people, and from the divine — and names the long era built on that worldview the 📝Age of Separation. In that usage separation is less an event than a story, reinforced by cultural habits such as 📝Labeling the World, and its counterpart is reunion.
I use separation in Eisenstein's sense: the isolated self, and the control it reaches for, is what I'm moving away from, toward the connection and abundance of the 📝Age of Reunion. In 📝Eco > Ego I put it plainly — greed and separation are increasingly experienced as highly inefficient.