Ob‐sid″i‐o‐nal (?), 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.