Piece vs. Song

[transitional]

You have to put text in this box for some reason.

[lelle]

I'd call anything written by a group who defines themselves as a "band" in the modern sense of the world, including a solo artist, a "song", regardless if it's a singer on it or just instrumental.

Anything written by someone defining themselves as a "composer" I would consider a "piece" or a "composition" unless it has a singer who sings lyrics on it, then it's also a "song".

Intuitively it feels pretty clear cut, but I'm sure there are edge cases. I would leave it up to the creator to decide how they want their music labelled.

[quantum]

You have to put text in this box for some reason.

Are you saying then, your post could be considered a song?   

[quantum]

I would leave it up to the creator to decide how they want their music labelled.

I'd agree with that.

The word "song" is used very loosely today.  Even with music production software, many things are referenced to the term song.  One creates a new file for a project, the software insists that it labelled as a song. 

[lostinidlewonder]

What about "Songs without words"? 

Anything that is meant to be sung with a voice I'm assuming is a "song". Whether that be a human or animal voice, birds don't sing pieces.

Instrumental works are "pieces".