TRILL n.
A sound, of consonantal character, made with a rapid succession of partial or entire intermissions, by the vibration of some one part of the organs in the mouth -- tongue, uvula, epiglottis, or lip -- against another part; as, the r is a trill in most languages.
ULTIMATUM n.
A final proposition, concession, or condition; especially, the final propositions, conditions, or terms, offered by either of the parties in a diplomatic negotiation; the most favorable terms a negotiator can offer, the rejection of which usually puts an end to the hesitation.
VACANT a.
having no heir, possessor, claimant, or occupier; as, a vacant estate. Bouvier. Vacant succession (Law), one that is claimed by no person, or where all the heirs are unknown, or where all the known heirs to it have renounced it. Burrill.