obsidional

a.

[L. obsidionalis, from obsidio a siege, obsidere to besiege: cf. F. obsidional. See Obsess.]
Of or pertaining to a siege.

Obsidional crown (Rom. Antiq.), a crown bestowed upon a general who raised the siege of a beleaguered place, or upon one who held out against a siege.

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IN BRIEF: adj.- Of or relating to a siege.