I suspect that this is yet another case of different people using words and symbols differently as each person follows their own Wiccan path, however I thought I would place my defintitions of these words as I use them, just for anyone who is interested.

A Pentagram is a five pointed star, and is usually something that is drawn either physically with a pen on paper or symbolically with a wand/athame in the air or on the ground. This symbol is used to invoke protection for a person, place or thing.
Just to mention here that a Pentagram within a circle is called a circumscribed (surrounded by a circle) Pentagram. The circle shape is used symbolically to contain the energy of protection raised by the casting of the Pentagram.
A Panticle (word first coined by Aleister Crowley) is a disc made from a natural material, (wood, clay, stone or metal) engraved with a five pointed star which is specifically used in ceremonial magic as an instrument of protection or a tool to envoke spirits. There are different designs for each of the planets, and many of the different uses they have also have slightly varying versions. They can be hung over doors, and windows to protect your dwelling, or because their energy is naturally passive, they are excellent when used to focus and ground yourself before performing spells for personal improvement or spells to draw money.
A Pentacle is a platter or large disc/plate on which is carved a pentagram. This is almost exclusively used to hold the altar offering of the earth element, be it salt/earth/grain etc.
Three seperate words, for three seperate objects used for three distinctly seperate purposes.