se⋅ren⋅i⋅ty | /səˈrɛnɪti/ | [suh-ren-i-tee] –noun, plural -ties for 2. 1. the state or quality of being serene, calm, or tranquil; sereneness. 2. (usually initial capital letter) a title of honor, respect, or reverence, used in speaking of or to certain members of royalty (usually prec. by his, your, etc.).
Origin: 1400–50; late ME serenite < L serēnitās. See serene, -ity