Slicing
Slicing is pretty much self-explanatory, and although there are variations, typically to slice is to cut the food into wide, thin pieces.
I will cover here a couple special styles of slicing:
Chiffonade
This style of slicing tends to be used on leafy greens such as spinach leaves. It is often used as a base for other foods or as a garnish.
To achieve a chiffonade, simply take an arranged stack of leaves and tightly roll them lengthwise. Then cut the role into thin slices, what you will end up with is a small pile of spinach strings.
The 'horizontal slice'
I don't know if this style of slicing has an official term but it's typically used on thicker protein items such as steak and chicken breasts. You can use it to cut the item in half or partially slice it so as to be able to stuff it.
To to this safely you will need to make sure your knife isn't dull, a dull knife will require you to work hard and you could easily injure yourself.
Simply place the palm of your off-hand, with your fingers slightly bent backwards, on top of the item being sliced, putting just enough pressure to keep it from moving. Using long, gentle strokes, making sure to keep the knife parallel with the cutting board, slice through the meat.