All 5 Uses

solemn
in
The Tempest
(Auto-generated)

[Enter ARIEL, invisible, playing solemn music] SEBASTIAN†
Scene 2.1

solemn = very serious--possibly dignified
[Solemn and strange music: and PROSPERO above, invisible†
Scene 3.3
The solemn temples
Scene 4.1 *

solemn = serious and dignified
and you whose pastime Is to make midnight mushrooms, that rejoice To hear the solemn curfew;†
Scene 5.1

solemn = very serious--possibly dignified
A solemn air, and the best comforter To an unsettled fancy, cure thy brains, Now useless, boil'd within thy skull!†
Scene 5.1

Definitions:

(1) (solemn)
in a very serious (and often dignified) manner
(2) (meaning too rare to warrant focus)
Less commonly, solemn can mean that something was done with great or appropriate ceremony. It can also be used to describe something as dark or undecorated.