As there seem to be few "pantheist witches" out there in the world, there is also not really a base definition for the term. (that I have found yet anyway!) So I decided it might be of some importance to extrapolate what I personally mean by it.
For me, I began to step away from the idea of polytheism as I began to feel drawn to calling on, well, everything. By everything I mean that divine essence that is all encompassing. I feel this mystical essence is within us and around us and in everything. I feel that it is an energy that I can work with. It is the energy I call upon and utilize in magickal working and healing and devotionals. So my personal practice has morphed into a mosaic of Pantheism, Panentheism and Animism. Among some of the definitions you find online for these terms are some personal slants from various religions. I assure you whatever way they have woven themselves into my being, they are 100% Witchy. My step away from polytheism, began with my inner dialogue that began to get louder and louder asking why I would call upon specific gods or goddesses. Why not call upon the thing that I feel is part of all of us? Why not work directly with that? So, that is what I began doing.
I don't know where the term "Sacred Divine" popped it's lovely name into my head from, but it did. If I feel compelled to use a name for that 'thing' I call on the "Sacred Divine." Part of why I do this is to set me in the middle of all that is, as working in concert with the All, the Source, the Universe, Divinity in all it's many splendorous forms. When I was aligned with a specific pantheon, I felt cut off from things outside of that pantheon. Little intuitive nudges I was getting from other areas of the spiritual realm went ignored by me because they didn't fit into the dynamics of the pantheon I had been working with.
There are many different types of Witches out there. Some staunch polytheists to some with no spiritual inclination whatsoever. Some who would claim that you must be initiated by another, some that would claim that self initiation is sufficient and still some that don't feel initiation is even necessary.
Now while I have not worked specifically with Gods or Goddesses in awhile, I do still have an open mind to believe they may be somehow a different kettle of fish altogether. Beings that can be called upon like Angels or Totems, Elementals and the like. After all, when polytheism was central to my practice I was connecting with something right? But that is a blog post for another day!