gaer is on the right track. I will get a little more technical...
"Ripping" is converting audio CD tracks saving them into audio formats such as... mp3, wav, wma, vqf, ogg.
From there you can "Burn" a CD taking the saved audio formats and transfering them to cd.
Just in case anyone cares about the origin of the term RIP:
RIP is an acronym for ...
* Raster-Image Processor, Remote Imaging Protocol, Routing Information Protocol
Raster-Image Processor is not the only word formed from RIP. There are 2 more listed below.
2) RIP is also derived from Remote Imaging Protocol
3) RIP is also derived from Routing Information Protocol
rip: Slang. To encode, compress, transfer, and copy digitized audio or video data from a compact disc (CD) to a computer hard drive. Note: Ripping is usually done with the intent of transferring those files to another user or another device.