Full Sun is directly in the path of the sun from sunrise to sunset. There are not many obstructions like trees, roofs or buildings.
Part Shade means that your plants get about 50% full sun in a day with a break of 50% shade.
Shade means that your plant does not get any sun at all. Keep in mind that shade does not mean darkness. You still need to put your plant in a place that will get diffused light. A good guide to use, if you are able to read a book in this area then the amount of light is just right.