According to the Recording Academy (which awards the Grammy):
Album of the Year is awarded to the performer, songwriter(s), and the production team of a full album if other than the performer.
Record of the Year is awarded to the performer and the production team of a single song if other than the performer.
My understanding is that a 'record' could refer to any recording that was pressed onto a vinyl disc. It could mean a single song, or a collection. The capacity of the discs changed as the technology progressed. The earliest commercially available records could only play about 10 minutes per side - thus making a collection of songs or a long performance (...