Kinktionary
More like guidelines and a lot less like definitions.
slave
A person who gives up total control to someone who they are in an agreed-upon dynamic and/or relationship with. The term slave is not gender specific. You can use “female slave” or “slave girl” to make a distinction between genders.
Slave in Core BDSM
In traditional BDSM/Core BDSM, the definition above may be considered incomplete or misguiding because slave is a title attributed to a submissive who enters a Total Authority Transfer, therefore effectively and irrevocably transferring all of their agency to their Dominant (who has the title of Master or Mistress) becoming their "property". It is, of course, a consensual process that must be negotiated at length before being entered into. Once the slave consents to the Authority Transfer, they are considered to be entitled to no further right of consent, their only recourse to the will of their Master being to withdraw consent to the dynamic as a whole, therefore ending it.
Most often the judgement, feedback, and personality of a slave are highly valued by their Masters, who employ a considerable amount of time, effort, and work in the development and happiness of their slaves.
A Core BDSM slave has nothing to do with historical slavery or any form of coercion.