Pentacle: The pentacle represents good, pure & white magick. A symbol of light & pure.
Firstly, it symbolizes the North, South, East, West, & the Spirit.
Secondly, it symbolizes the Earth, Water, Air, the Spirit, & the Divine.
Third, it symbolizes the God & the Goddess. If encased within a circle, it means wholeness & unity of all quadrants & the elements & our ultimate love for nature.
Pentagram:
The pentagram is actually a symbol of spiritual shielding & ethereal world intelligences.
It is also a symbol of the mind dominating over the elements.
The bad spirits & other negative elements are powerless when faced with this symbolizes.
Good spirits are drawn to it.
Those she have this symbol have infinite possibilities at their disposal.
Some do attribute the pentacle as directional symbol, but it doesn't actually indicate such as it's 5 points not 4. I've also seen people attribute it to Jesus head, arms and legs. In general a pentacle is a pentagram enclosed in a circle.
A pentagram is the star symbol not enclosed.
People have adopted different meaning over the years, I'm too old to keep up with them.
My own perspective on the pentacle versus pentagram is pretty simplified. Tome the pentacle resonates as a symbol of invocation; Accessing and drawing within (towards yourself) energies and intent. Meanwhile the pentagram is the reverse; Evocation (sending outward or away) of energy and intent.
The simplest difference is that the Pentagram is any five-pointed star whether used for magic or not. The Pentacle, on the other hand, is a five-pointed star within a circle.
The pentacle has been used in a number of cultures. As I mentioned earlier, in early Christianity it represented the five wounds of Christ within the Crown of Thorns. In some magical traditions, particularly Wicca, it represents the Elements of Earth, Air, Fire, Water, and Spirit all held within the Universe.
Let me also clear up some misconceptions about the "inverted" Pentacle. In movies and novels this is always seen as a symbol of evil. This is not actually true. Yes, there are some groups who use it in this manner, but such usage is not universal.
In some forms of Satanism, namely the Church of Satan, it is used to represent Baphomet and is a symbol of that particular form of Satanism. Note that the Church of Satan is largely atheistic and should not be considered as evil or negative.
Also, the inverted Pentacle is seen in some forms of Traditional Wicca, often to denote someone who has attained their Second Degree. The upright pentacle is seen as sending energies upwards towards to Divine. In contrast, the inverted Pentacle draws Divine energy downwards towards Earth and represents a giving back to the community or the earth itself.