2481: Octet
19 across (two words) is commonly associated with an octet. Each member of the octet defines one further unclued light. Across 11 Masseur also kneaded old reptiles (11)12 Country’s northern frogs, newts etc with no acid measure (7)13 Tease one brunette, vacuous crone (6)16 Very great network’s backing Sturgeon (7)17 Personify old emperor and knight,