When was the terminology *tracing collector* introduced to denote both mark-and-sweep and copy collectors
The terminology was introduced in Lang and Dupont, Incremental Incrementally Compacting Garbage Collection, SIGPLAN 87. This is the paper which consolidated several lines of enquiry into one common language.

The way I found this out was by consulting Paul Wilson's 1992 survey, Uniprocessor Garbage Collection Techniques, which is required reading if you need to know stuff like this.