The term AOR, as in Album Oriented Rock, was first used in the seventies to describe the then new format of FM rock radio stations that specialized in playing album cuts, digging deeper into a record than merely spinning the singles heard on more pop oriented radio. The AOR format idea, which over the years disintegrated into boring predictable programming by "suits" whose bottom line was profit, not good music, began its days as a somewhat noble idea; one that borrowed the progressive and freeform radio pioneered in the years just before its launch by such adventurous programmers as the late great Tom Donahue at KMPX and KSAN in San Francisco.
But before there was AOR, there was MOR, a format that never pretended to be hip or alternative or adventurous in any way. Most popular in the sixties and seventies, MOR, as in Middle Of the Road, was, as its name implied, a most mainstream radio format whose playlist offered a mix of non-offensive popular music. Middle Of The Road was not the type of music that a self-respecting "artist" would claim to be but it was also the name that a successful 70's Scottish pop band chose. Although technically more bubble gum pop, Middle of The Road sure managed to appeal to a middle of the road audience and also scored a string of pop hits in the early 70's, including their 1971 debut single, "Chirpy Chirpy Cheep Cheep," which shot to #1 on the UK pop charts that year and went on to sell over 10 million copies. The hit captured Middle Of The Road's pure, unadulterated sugary pop, and their singalong sound. To me, their infectious Europop style and the fact that Middle of the Road included male and female pop vocals harmonizing made the group sound similar to Abba's style, whom they predated by a couple of years. Sweden's Abba formed in 1972 and scored their first pop hit ("Ring RIng") in 1973.