What is Oneness?

I read an Instagram post by Teal Swan today, and thought I'd elaborate some. A common topic among seekers, is Oneness. But what is it really?

Oneness to me, is a realisation that we, as humans, are coming forth from the same spiritual source and are interdependent through the eco-system. It's realising that all others have the same needs and emotions as you have. However, this doesn't mean we should not separate ourselves. In fact, we need separation to show our uniqueness and find autonomy. This is what the purpose of our personalities are. We need separation, but not to feel outcasted. Unfortunately, many "spiritual teachers" claim that the we should let go of ourselves in favor of following them, which is how cults are born. Everybody likes and follows, but few seem to dare question. Would we not evolve and heal better if we had more discussions about how to define things, rather than to assume guru-ship?

To be one with nature, is to recognize and feel that we host the same spirit, the lifegiving force that some may call Prana, others Chi or Mana, the spark of light that can show in our eyes. This aliveness evokes a feeling of being part of something greater, which can be called oneness.

To be one with another person, is a moment of bliss but can never be lasting, since we all are in a constant motion of pushing and pulling in relation to others and our environment. The greatest love might even be to see, accept and validate what is different about the other, and express appreciation for that.