Classic hits is a radio format which generally includes rock and pop music from the early/mid 1960s through the mid/late 1980s (sometimes early/mid 1990s). The format, which came in vogue around the beginning of the 21st century, is considered as a contemporary version of the oldies format. The term is erroneously used as a synonym for the adult hits format, which uses a slightly newer music library stretching from the 1970s through the present.
The term "classic hits" is believed to have its birth at WZLX Boston when the station converted from adult contemporary to a format composed of the hipper tracks from the oldies format and album tracks from popular classic rock albums. The goal was to attract and magnetize people who experienced adolescence in either the 1960s and 1970s and enjoyed the music of those eras, but did not care for the then-current heavy metal or top 40 music of the 1980s. These were people whose mindset was getting too old for AOR and top 40, but were too young for or not interested in oldies.
Over time, the "classic hits" format has evolved into more of a stations' tagline than of a tightly focused music library shared by the stations who use the term. The stations are merely oldies stations that evolved into a more up-tempo sound with more newer songs, and the term is now considered a more appealing name than "oldies" to listeners and advertisers alike. Westwood One's national classic hits network describes its format as "pop, soul and rock and roll." Most "classic hits" stations predominantly air music from the 1970s; the general trend has been to cut back on 1960s music and add more 1980s music as the years have progressed.
Until the past few years, most classic hits stations have either leaned towards pop hits of the 1960s through the 1980s or were actually classic rock stations without a lot of hard rock. Classic hits stations typically do not play pre-1964 music, except for a few especially popular or enduring songs such as early Beach Boys hits, or more generally 1960 to 1963 songs. In most cases, more pop-leaning classic hits stations evolved quietly and gradually from being traditional oldies outlets. The classic hits format as heard in the early 2010s is noticeably similar to rhythmic oldies, a disco-centric format that was popular in its own right during the late 1990s and early 2000s.