Key-Frame: A key frame in animation and filmmaking is a drawing that defines the starting and ending points of any smooth transition. The drawings are called "frames" because their position in time is measured in frames on a strip of film.
Vector: Web-based graphic file format, alternative to pixels
Stroke: To apply (something) to a surface using gentle movements 
Fill: Filling in a shape with a color / Achieved by using the paint bucket in Flash
Stage: a point, period, or step in a process or development / Work Area in Flash
Symbol: any object or combination of objects
FPS: Frames per second
Frame: A still image multiple are used and put together to create movement in a still 
FLA: An Adobe Flash File
SWF: A Shock Wave File - Small Web Format
MOV: A common multimedia file format

-Squash and Stretch is what gives flexibility to objects. There’s a lot of squash and stretch happening in real life that you may not notice; in animation this can be exaggerated. For instance, there’s a lot of squash and stretch that occur in the face when someone speaks, because the face is a very flexible area

-Anticipation is used in animation to set the audience up for an action that is about to happen. An easy way to think about this is that if a person needs to move forward, they first must move back. For example, if a character is about to walk forward, they might move back slightly, this not only gets their momentum up, but it also lets the audience know this person is about to move. Or if a character is reaching for a glass on a table, they might move their hand back, before moving it forward

-Staging is how you go about setting up your scene, from the placement of the characters to the background and foreground elements and how the camera angle is set up. The purpose of staging is to make the purpose of the animation unmistakably clear to the viewer. This could be ensuring the camera is set up in a way to communicate the characters expression clearly, or setting up two different characters so that both of them are easily viewed from the specific angle

-Straight ahead and pose to pose refers to the two different techniques for how you go about animating. With straight ahead it’s a very spontaneous and more of a linear approach. You’ll create each pose or drawing of the animation one after the other. For example, if you’re animating a character jumping in the air you would create the pose where he’s standing, the next where he is beginning to kneel down, the next would be him completely crouched, and so on. You’re really working through the animation as you’re going

-Follow through is the idea that separate parts of the body will continue moving after the character has come to a stop. For example, as a character comes to a stop from a walk, every part of the body won’t stop at the exact same time, instead, the arms may continue forward before coming to a settle. This could also be articles of clothing that continue to move as the character comes to a stop

-Overlapping action is very similar in that it means different parts of the body will move at different times. For example, if a character raises their arm up to wave, the shoulder will move first, and then the arm, and the elbow and hand may lag behind a few frames. You may have also heard this referred to as “drag” or “lead and follow” You can even see an example of overlapping action in something like a blade of grass, the base moves first, and the rest of the grass follows behind at different rates, giving you that waving motion

-As any object or person moves or comes to a stop there needs to be a time for acceleration and deceleration. Without slow in slow out, movements become very unnatural and robotic. For example, as a car starts from a stop, it doesn’t just reach full speed in an instant, it first must accelerate and gain speed. As it comes to a stop it doesn’t go from sixty to zero in the blink of an eye, if it did, it would be extremely uncomfortable. Instead, it slowly decelerates until it reaches a complete stop

-Everything in real-life typically moves in some type of arcing motion, and in animation you should adhere to this principle of arcs to ensure your animation is smooth and moves in a realistic way. The only time something would move in a perfectly straight line is if you’re trying to animate a robot, because it’s unnatural for people to move in straight lines

-Secondary action refers to creating actions that emphasize or support the main action of the animation; it can breathe more life into an animation and create a more convincing performance

-Timing and spacing in animation is what gives objects and characters the illusion of moving within the laws of physics. Timing refers to the number of frames between two poses. For example, if a ball travels from screen left to screen right in 24 frames that would be the timing. It takes 24 frames or one second (if you’re working within the film rate of 24 frames per second) for the ball to reach the other side of the screen

-Exaggeration is used to push movements further to add more appeal to an action. Exaggeration can be used to create extremely cartoony movements, or incorporated with a little more restrain to more realistic actions. Whether it’s for a stylized animation or realistic, exaggeration should be implemented to some degree

-In 2D Animation, solid drawing is about creating an accurate drawing with volume and weight, and thinking about balance, and the anatomy in a pose

-This principle can really come down to adding more appeal in many different areas of your animation, such as appeal in posing. However, the most obvious example is appeal in the character design, you want to have a character that the audience can connect to or relate to. A complicated or confusing character design can lack appeal