What does "solemn" mean?

Additional senses

1. 2.Stately; ceremonious; grand. [Archaic] His feast so solemn and so rich. Chaucer. To-night we hold a splemn supper. Shak.
2. 3.Fitted to awaken or express serious reflections; marked by seriousness; serious; grave; devout; as, a solemn promise; solemn earnestness. Nor wanting power to mitigate and swage With solemn touches troubled thoughts. Milton. There reigned a solemn silence over all. Spenser.
3. 4.Real; earnest; downright. [Obs. & R.] Frederick, the emperor, . . . has spared no expense in strengthening this city; since which time we find no solemn taking it by the Turks. Fuller.
4. 5.Affectedly grave or serious; as, to put on a solemn face. "A solemn coxcomb." Swift.
5. 6.(Law) Made in form; ceremonious; as, solemn war; conforming with all legal requirements; as, probate in solemn form. Burrill. Jarman. Greenleaf. Solemn League and Covenant. See Covenant, 2. See Grave.