obsĭdĭum (noun N) : obses
* The condition of a hostage, hostageship (Tacitean): Meherdates obsidio nobis datus,Tac. A. 11, 10.

obsĭdĭum (noun N) : obsideo
* A siege, investment, blockade (mostly ante-class. and post-Aug. for obsidio; not in Cic. or Caes.; but cf. obsidio).
* Lit.: obsidium dictum ab obsidendo, quominus hostis egredi posset inde,Varr. L. L. 5, § 90 Müll.: obsidium, tam quam praesidium, subsidium, recte dicitur, Paul. ex Fest. p. 193 Müll.: saevo obsidio premere aliquem, Enn. ap. Non. 216, 29 (Ann. v. 28 Vahl.): obsidium facere Ilio,Plaut. Bacch. 4, 9, 24: obsidio circumdare,Tac. A. 13, 41: obsidium urgere,id. H. 4, 28; Flor. 4, 4, 4; Gell. 15, 31, 1; Amm. 20, 7, 3: ad liberandum Mogontiaci obsidium,Tac. H. 4, 37.
* Trop.
* A waylaying, an ambush: obsidia hominum aut insidiosorum animalium,Col. 8, 2, 7.
* Attention, foresight: curatoris,Col. 9, 9, 1; cf. obsidio.
* Danger: tuo tergo obsidium adesse,Plaut. Mil. 2, 2, 64.

s. TLL