'Slavery is, in the strictest sense of the term, any system in which principles of property law are applied to people, allowing individuals to own, buy and sell other individuals, as a de jure form of property. A slave is unable to withdraw unilaterally from such an arrangement and works without remuneration. Many scholars now use the term chattel slavery to refer to this specific sense of legalised, de jure slavery. In a broader sense, however, the word slavery may also refer to any situation in which an individual is de facto forced to work against his or her will.'
Note:
'In a broader sense, however, the word slavery may also refer to any situation in which an individual is de facto forced to work against his or her will.'
'Slavery is, in the strictest sense of the term, any system in which principles of property law are applied to people, allowing individuals to own, buy and sell other individuals, as a de jure form of property. A slave is unable to withdraw unilaterally from such an arrangement and works without remuneration. Many scholars now use the term chattel slavery to refer to this specific sense of legalised, de jure slavery. In a broader sense, however, the word slavery may also refer to any situation in which an individual is de facto forced to work against his or her will.'
Note:
'In a broader sense, however, the word slavery may also refer to any situation in which an individual is de facto forced to work against his or her will.'
The broader description isn't a metaphor.
[0] https://en.wikipedia.org/wiki/Slavery