I've never seen or heard slave songs refered to as anything else but slave songs. Some might brake that down a little. I asked Frankie Quimby of the Georgia Sea Island Singers about a song & she said "oh that's an old time slave song", on the other hand, older now deceased members of the same group refered to some work songs as a rowing song (going back to slavery days) & on loading lumber on deck, a chantey or just a plain work song. She also called some Code Songs, like to let slave people know that Harriet Tubman was coming through without letting on to the slave holders (this I'd say is a contempory term). Some of the older long moaning slow songs, sung solo while picking cotton might be called a field holler (could also be called a cotton or cane song) but that may be a label applied by recent collectors. After slavery days you may have a muleskinner singing to his mule some camp levee holler & in prison you'll have some songs refered to by the work they accompany (like capstan, pump & halyard shanties), hoeing or flatweeding, chopping or crosscutting or logging songs, but these wouldn't be slave songs. As long as the horses didn't sing them they'd be folk songs. Barry