It doesn’t matter which dictionary you consult, they all agree on what a song is: words, set to music, that are sung. Yet it’s also an entirely inadequate description, since there are so many types of song.

Take David Gilmour and Neil Finn, both men of passing years who like to switch between electric and acoustic guitars, both backed by plenty of singers and kindred instrumentation (though Finn didn’t have a pair of harps on stage with Crowded House), both playing music largely rooted in the late 1960s, both offering lightly mind-bending songs.