In the song "another one bites the dust" what are they talking about?

It looks to me like there are bullets hitting the ground, in other words biting the dust.

@YARNLADY Hmm. I think biting the dust refers to the teeth of a human when they are killed and fall forward into the dirt. Homer describes this frequently in The Illiad. Of course the expression if often used just to mean someone is taken down/out, not necessarily to death, nor literally with teeth hitting dirt.

The lyrics seem to be about hunting down a large number of people and killing them with a machinegun, and the lines:

There are plenty of ways you can hurt a man
And bring him to the ground

seem consistent with this, to me.

The St Valentine’s Day Massacre or some other famous MOB hit?

I always thought it meant that he was dumped by yet another partner. Probably because of this verse:
How do you think I’m going to get along
Without you when you’re gone
You took me for everything that I had
And kicked me out on my own

It’s a song about the world’s worst restaurant.

The supposedly idiomatic phrase: “another one bites the dust”—is actually meant to be taken literally.

I thought the writer was describing how he was treated by his girlfriend. The way he was dumped felt like being ambushed in the street, the latest in a long line of victims..

You can read the lyrics here: https://www.google.com/search?q=lyrics+%22another+one+bites+the+dust%22

What that means is up to you. Always remember that a song does not have to mean anything, it only has to have good rhythm, nice tune, and memorable lyrics. “Louie Louie” is a famous example: the FBI diligently listened to that record for months and finally concluded that it was unintelligible at any speed.

It was the song the instructor played when I was learning CPR for the first time at nursing school. The idea was to do the chest compressions in time with the song.