- clear; bright; unclouded: a serene sky
- not disturbed or troubled; calm, peaceful, tranquil, etc.
- exalted; high-ranking: used in certain royal titles: his Serene Highness
L serenus < IE *ksero-, dry (> Gr xēros, dry, OHG serawēn, to dry out) < base *ksā-, to burn
Old Poet. a serene expanse, as of sky or water