MOR is a style of music that has become increasingly popular in the 1970s. The letters stand for "Middle of the Road" and the music, more often than not, stands for "dollars and cents." The record industry, in its mad rush for corporate profits has embraced this music for its lack of daring, it's monotonous sameness and the resultant capital - investment potential that is based on a market that buys what it is told by radio and promotion campaigns.

Helen Schneider is a singer who has garnered a certain amount of attention in this country and Europe as the result of two records and TV and club appearances. Her show at the Cellar Door last night, before an enthusiastic crowd, was the epitome of the MOR philosophy.

Schneider and her six-piece back-up group featured a tightly paced set that drew from various musical styles - rock, pop and blues - yet somehow managed to reduce each of these to a dull and lifeless musical glop. She was always on key, the group never missed a note or a beat - everything was exactly right, very safe and musically arid.

Most of her material was drawn from her record, including "Loneliness" written by Paul Williams, yet despite the differences in tempo and accent, the songs sounded pretty much the same.

All of which is regrettable, because Schneider is a fine singer with a wide vocal range and an expressive style. If and when she becomes more awed by making music than by making money, she and her listeners will be all the richer.