The principle of international law where states believe or accept that a practice exists and must be followed because of a rule of law requiring it, to the extent that it becomes part of the body of norms known as international Customary Law.

A surname.

Third-person singular simple present indicative form of siver

present participle of siver

simple past tense and past participle of siver

(obsolete) To simmer.

An inhibitor of human neutrophil elastase, used in the treatment of acute respiratory failure.

A surname.

plural of Sivertson

plural of Sivertsen