http://www.sacred-texts.com/bos/bos210.htm
from Internet Book of Shadows, (Various Authors), [1999], at sacred-texts.com
The primary meaning of “pantheism” is “the belief that the Divine is identifiable with the forces of nature and with natural substances,” and it is this meaning of pantheism which is properly contrasted with “panentheism” (the belief that the Divine is within the natural world but not limited to it). This pantheism *denies* all Gods and Goddesses, at least to the extent that They are understood as anything more than natural forces. Thus if you believe that the Goddess is something more than the physical planet Earth, you are NOT a pantheist; you are a panentheist.
A secondary meaning of “pantheism” is “worship that admits or tolerates all gods.” As this meaning directly contradicts the primary meaning, persons using the term should be careful to specify which meaning they intend. (Under this meaning, if there is any god whose existance you do not acknowledge — Satan, for example — you are NOT a pantheist.)
Within the pagan community, the term pantheism is used even more sloppily as a synonym for polytheism and/or animism. This had led many people who don’t meet either of the above definitions to mistakenly call themselves pantheists.
By that, I mean that I believe the Christian God exists, but don’t necessarily worship that particular deity. If all gods and goddesses exist, you can worship one of them (Monotheism), without excluding the existence of the rest of them.
That’s not monotheism, that’s henotheism. Monotheism is the belief that only one “God” exists. Note, however, that monotheism does not deny the existance of lesser beings (saints, angels, etc.) who might also be called “gods” in a polytheistic system. Note also that Christianity is not truely monotheistic, as it has the top job shared three ways.