Bake - what you do when you stick something in the oven. Heat surrounds the food, cooking evenly from all sides. The 'default' temperature for cooking is 350.
Baste - Scoop up cooking juices and pour over the food. Helps keep food from drying out.
Boil - what water does around 212 degrees Fahrenheit. Several different kinds:
Almost-boil: tiny bubbles on the bottom and sides of the pot. Size of a pencil tip. Some steam comes off the top of the water
Simmer - small bubbles on the bottom of the pot. Size of a pencil eraser. Bubbles join together and come to the top. Steam comes off the top of the water.
Full boil (sometimes called a 'rolling boil') - large bubbles popping too fast to easily identify. Looks like you've put a straw in a glass of water and are blowing bubbles through it very hard. Steam is harder to see (it's condensing higher above the pot)
Broil - a cooking method where the heat source is above the food. Most ovens have a 'broiler' under the main stove; it looks like a pull-out tray.
Dice - to cut into cubes. Sizes are usually approximated.
Fry - a cooking method where the food is immersed in hot oil.
Poach - a cooking method where the food is immersed in hot (but not boiling) water.
Pot - Basically, a tall-sided pan. Used mostly to boil things. Generally three sizes:
Small pot - holds 2 16ounce cans of stuff, or about 4 cups of water. You'd make a cup of ramen in it.
Medium pot - holds about 3 28ounce cans of stuff, or about 12 cups of water. You'd boil a box of pasta in it.
Big pot - holds about 8 28ounce cans of stuff, or well over 20 cups of water. You can fit a whole chicken in this pot.
Really Big Pot - Holds more stuff than I've ever tried to put in it. I don't actually have a pot this big, my mother does. It's really only used for boiling corn on the cob, and we can fit about 2 dozen ears in it at a time.
Puree - (Pure-ay) Toss it in a blender. Turn blender on.
Reduce - to cook over medium-low heat and evaporate water. This is used to strengthen flavors and thicken sauces. Foods are mixtures in the true chemical sense of the word - they can be separated by physical means. Reduction is heating a food to the point where the water of the mixture is boiling and evaporating out, but the mixture as a whole is not boiling. Foods that are reducing usually look like they're simmering, but are hotter than 212 F.
Roast - a cooking method where food is cooked at a high temperature (above 400) until it is completely done.
Roux - (roo) fancy french word for equal parts flour and melted butter. Used to thicken sauces.
Saute - (saw-tay) a cooking method where the food is cooked in a small amount of fat, either oil or butter.
Sear - a cooking method where the food is quickly cooked at a high temperature. Yields a blackened out side and a raw inside. Usually foods are seared first for texture and color, then finished cooking in a different method.
Saucepan - Ah, the ubiquitous saucepan. If it's wider than it is tall, it's a saucepan. Otherwise it's a pot. Functionally, pots and pans are the same thing; pans just give you a wider cooking base, allowing the food to cook more evenly. Generally three sizes:
Small saucepan - About 4 inches across (spread your fingers - tip of thumb to tip of pinkie). Usually used to cook eggs or make small batches of sauces.
Medium saucepan - the most used pan in your arsenal. About 12 inches across (about the length of your forearm). Used for nearly-everything. If you're starting a kitchen, having two of these will make your life easier.
Large saucepan - Biggest pan, and almost deep enough to be called a pot. Mine's a bit wok-like: it has curved edges and a relatively small flat bottom.