a legally recognized secondary wife: a woman in a genuine but lower-ranking marriage bond
The word does not mean mistress or slave. Every major modern lexicon converges on a secondary-wife reading: a woman whose husband is her legitimate איש and whose father holds the status of father-in-law to the husband. She differs from a full wife (אשה) primarily in the absence or reduction of the formal marriage payment and in the attenuated inheritance rights of her children, not in any lack of legal recognition.
Across the canon the institution performs distinct narrative functions. In the patriarchal stories it is a genealogical instrument: the secondary-wife line produces sub-tribes assigned to a lower covenantal tier than the primary-wife line (Nahor's Reumah, Keturah as retrospectively classified, Timna generating Amalek). In Judges and the Davidic narratives the political function dominates: taking the king's secondary wives is a public act of dynastic succession-claim, not a personal indiscretion. Absalom's act on the rooftop, Abner with Rizpah, and Adonijah's request for Abishag all operate by the same principle. In Esther and the Chronicler the term generalizes into an imperial-harem or genealogical-administrative label. These different deployments reflect different narrative contexts, not different word meanings: the legal concept is stable throughout.
The word itself is a borrowed term, almost certainly from a Mediterranean cultural source shared by Greek pallake (secondary wife) and Latin paelex, rather than borrowed from either direction. Its four-consonant skeleton with no productive Hebrew morphological pattern identifies it as a foreign body in the lexicon, a designation for an institution that pre-existed any one language's coinage for it. The Septuagint's consistent rendering with pallake (never doule, the word for "slave") confirms that ancient translators understood the term as marital, not servile.