Sederunt \Se*de"runt\, n. [L., they sat, fr. sedere to sit.] A sitting, as of a court or other body. 'T is pity we have not Burn's own account of that long sederunt. --Prof. Wilson. {Acts of sederunt} (Scots Law), ordinances of the Court of Session for the ordering of processes and expediting of justice. --Bell.