Can someone plaease explain to me in lay terms the difference between:

an audio editor, a sequencer, a digital audio workstation, a sample editor software with mastering tools.

Thank you!

There are no short answers to these questions so go to:

http://www.computermusic.co.uk/basics/basics.asp

It's Computer Music magazine's link. When I first started out I subscribed to their mag. It was at that time mostly for newbie's (such as myself at the time). It helped me a lot. I'm sure it will help you as well.

An audio editor is just that. In an audio editor you will see your audio file in wave form. You can make changes to the wave form, and see (and hear) the changes made, such as making it quieter, fading, cutting parts out, or moving the file foward or backwards in time.
An audio sequencer allows you to work on muliple audio wave forms. The sequencer will let you allign the timing on all the tracks, so they match, or you can see where to do fades or cuts, relative to the other audio tracks. A digital audio work station or DAW can either be your computer, or a stand alone unit. The stand alone DAW usually has a mixer, effects, built in CD burner, and other tools nessasary to master audio works. Sample editing software with mastering tools is a bit more complicated. Sampling is using actual recorded sounds. These can either be loops, or they can be a simple as a snare drum hit (sound font). In order to use samples you have to be able to get the sample to start at zero crossing (right when the sample starts to make an audio wave) and must also end at zero crossing. This allows for seemless use of samples, with out pops, or unwanted silent spaces(loops).
That's about as simple as it can be stated.