We never heard the word classic rock until the songs of the late 60's , 70's and into the 80's ( now even 90's and early 2000's) needed a new format to differentiate it from the current (of the day) rock stylings. Programmers needed to draw a line somewhere, although in music that line seems to drift over time.
That was not a programming decision. The name "classic rock" came out of station owners, managers and, particularly, sales managers who needed a term that "nicely" described a kind of rock that fell into the category that many ad buyers would otherwise call "old hippie music" or worse.
In general format names are intended to help in sales where many clients and ad agencies have no idea what format a station has.
Oldies was already taken, and the songs formerly known as oldies were relabeled golden oldies.
"Oldies" became stigmatized as "the music of my grandparents" at the agency level among Heather, Dawn and Ashley... the twenty-something junior media buyers at agencies. So the industry sort of settled on "classic hits" for the now-80's-based CHR hits format.
In many cases, we don't use those terms "in house" as they are meaningless.
Example. In 2000 PD Amalia González and I created, based on research, the Spanish language format now called "Spanish Adult Hits" in Nielsen reports. The format had never existed before, neither in the US nor Mexico. But when the format became very successful and even imitated, sales needed a name to suggest to Arbitron. So the sales people took the title given to all the "Jack" and friends formats and added "Spanish" to it and Arbitron got enough "yes" votes from station managers to create the new term to add to the limited list of acceptable format names used in the ratings reports.
We never, ever, used the format name in-house. It was meaningless for programming, and even less relevant to listeners.
