Arguably its a mistranslation since most “slavery” in Taanach refered to long term labor contracts, lacking many critical aspects of what in English is referred to as slavery (owners weren’t allowed to kill slaves, prohibition of sex with slaves, etc.).
American style “slavery” has no word in Hebrew since the concept is unknown. In truth, the barbarity of American slavery has few equivalents to anything in our experience (the holocaust came close, but that’s it), which probably explains why there is no word for it in Hebrew.
Roman slavery was a little bit closer to American slavery, but still was radically different (freed slaves had rights, and their children were full fledged citizens, and by the end of the Imperial period, Roman slaves could go to court if they were mistreated). In truth, American slavery was probably among the most savage in human history, and not surprisingly, it was abolished after a short time (it began in the 17th century, and lasted only until the middle of the 19th, and was always abolished by most of the USA by the early 19th).