Definitions for "Kill ring"
The kill ring stores text which has been killed, so that it may be recovered at a later date. Text can be re-inserted into a buffer by yanking. There is only one kill ring for all buffers so that text can be copied from one buffer to another.
A history of parts recently deleted. This is called a "ring" because it can be rotated by the "Paste" command. See the "Kill Ring" section for more details.
under Emacs, it is the set of text areas cut or copied since the starting the editor. The text areas may be recalled to be inserted again, and the structure is ring-like.