a widow: a woman whose husband has died and who is left without his protection and support
In the Bible a widow is not simply a woman who has been bereaved. The word points to her changed standing in the world: with her husband gone she has lost the man who provided for her, spoke for her in legal matters, and shielded her from those who might take advantage. That is why she so often appears beside the orphan and the foreigner. These are the people with no one to defend them, and God repeatedly makes their care a test of whether a society is just.
The senses below are not different definitions of the word. They are the same person seen from different angles. Most often she is named as a real, specific woman. Just as often she stands for a whole class of the unprotected, the people the law and the prophets insist must not be exploited. And at times a fallen city or nation is pictured as a widow, stripped of the protector who once kept her safe.
Readers should feel the weight the word carried. To call someone a widow was to name both a grief and a danger: she had lost her husband, and with him her place of safety.