adj. & n.
adj. (serener, serenest) 1 a (of the sky, the air, etc.) clear and calm. b (of the sea etc.) unruffled. 2 placid, tranquil, unperturbed.
n. poet. a serene expanse of sky, sea, etc. all serene Brit. sl. all right. Serene Highness a title used in addressing and referring to members of some European royal families (His Serene Highness; Their Serene Highnesses; Your Serene Highness). serenely adv. sereneness n.
[ L serenus ]