oscillator-is something that creates oscillation. Yes, you're not supposed to define the word with the word you're using....but that's what it does. In our world it creates oscillations in sound. And what is an oscillation? It's a variation of a measurement over time. Think of a wave form. A complex wave form (ie. when you speak into the microphone) has it's oscillation changing all the time...it's never constant. However, if you run a 1kHz sine wave through your speakers you get a constant oscillation. We use oscillators to create these constant oscillations so that we have a pure 1kHz tone to work with.
Which leads into your next question:
Test tone- This is a tone use to test and set equipment levels. Because of the variations of analog and digital gear and the differences in their output levels, an engineer can use a test tone (typically 1kHz sine wave) as a standard. For example, video tapes in the post production world all contain a sine wave at the beginning usually at or around -20dBFS. When this plays back on someone else's tape player it lets that person know where the zero was at on the other system. Very important when you're going from digital to analot as well since the decibel scale is different.
sine wave- I've already been talking about this, however to be more specific think back to calculus math (assuming you've taken it) and think of a sine curve...remember that whole sine/cosine thing? In the audio world we consider this a pure tone or rather a single frequency with no overtones included in it. This is what you will use as test tone, generally.
pink and white noise-
These fall into different categories of which is known as colors of noise. There are various frequency characteristics of each of these things and physicists and engineers alike will use them for different things. White noise contains an equal distribution of energy spread over all frequencies, similar to white light. White noise can be helpful in determining the frequency response of mechanical equipment.
With pink noise instead of having equal energy at all frequencies...it's energy within each successive octave is the same but is reduced by half the power than the previous octave. Pink noise is different than white noise and probably something you'll find more pleasing to the ear. This has to do with how it reacts with the ear and how it compensates in the lows because of the increased number of frequencies in the highs. Pink noise is used mainly for testing/calibrating speakers or your room.
Take a look at this for some good graphical representations on the colors of noise:
http://en.wikipedia.org/wiki/Colors_of_noise
It's good to read up on these things and learn what they are, but most home recordists will never use them. If you get really serious about how you're room/speakers sound or do a lot of digital to analog transfers...you probably won't need it too much. But it doesn't hurt to learn
