The Zoom manuals suffer from some bad terminology at times. The use of the word 'song' is the worst offender.

Zoom multitrackers normally include Zoom drum machines built in. In Zoom drum machines the word 'Song' is used to describe patterns collected together in a progression. Unfortunately the terminology transfered over to the multitrackers. This obviously left a need for a new word to describe what you and I and any normal person would call a song. This was 'Project'

See Rhythm Song