Definition of "slain"

[…] Morat ! the proud, the patriot field ! where man / May gaze on ghastly trophies of the slain, / Nor blush for those who conquered on that plain ; / Here Burgundy bequeath'd his tombless host, / A bony heap, through ages to remain, / Themselves their monument ;— the Stygian coast / Unsepulchred they roam'd, and shriek'd each wandering ghost.

1816, Lord Byron, “Canto III”, in Childe Harold’s Pilgrimage. Canto the Third, London: Printed for John Murray, […], stanza LXIII, page 36

While the Valkyries were the choosers of the valorous slain, they were also obedient to the call of any in distress who asked their help.

1906, Mary Elizabeth Lewis, The ethics of Wagner's The ring of the Nibelung, page 41