Paying someone for labor kind of does make it not slavery - by the very definition of the word "slave" and "slavery".

Or are you attempting to redefine the word "slave"?

Nope, that is not the distinguishing factor. Historically, money was used as an incentive for slave labor done especially well. That does not prevent it from being slavery.

https://www.historyextra.com/period/slave-labour/

You have an uphill battle to convince anyone being paid (any amount) for voluntary labor is akin to slave labor.

I take issue with describing it as "voluntary", when the alternative is a longer prison sentence. It is paid a pittance, and is effectively involuntary.

> when the alternative is a longer prison sentence

That's simply untrue.

"Even though, in a lot of cases, it is technically voluntary, there can be serious consequences for people who refuse to work or who advocate for better working conditions because a lot of prisoners use working as a way of having their sentences reduced."

Source: https://www.npr.org/transcripts/884989263

In that section of the article they are discussing labor internal to the prison, specifically maintenance and daily chores. Yes, it is true, while in prison you do not have a choice but to participate in that kind of labor and refusal will not help you be released early for "good behavior" or anything similar.

External labor, the kind discussed here - contracted by a 3rd party for money - is voluntary.

Modern slavery in the US often works by bringing people in from another country, requiring them to pay for lodging and food at a "company store," and paying low enough wages that their debt steadily increases. Then you hold their passports and tell them they can't leave until they're paid up.

It's illegal, of course, because it's literally slavery despite the window-dressing of money changing hands. But the slaves are vulnerable and don't necessarily know it's illegal, or they're threatened.

Examples?