Definition of: serene

(si·rēn′) adjective
1. Clear, or fair and calm; having its brightness undimmed: a serene sky.
2. Marked by peaceful repose; tranquil; unruffled; placid: a serene spirit.
3. Of exalted rank: chiefly in the titles of certain continental European princes: His Serene Highness. See synonyms under SEDATE.
—noun Rare or Poetic
1. Clearness, or a serene or clear region.
2. Calmness; placidity. [<L serenus]
—se·rene′ly adverb
—se·ren·i·ty (si·ren′ə·tē), se·rene′ness n.