B / bĭlustris
adjective

bĭlustris

neut. bĭlustre
bis - lustrum
that lasts two; ten years; of ten years
that lasts two lustra, i. e. ten years, of ten years' duration (very rare): bellum, Ov. Am. 2, 12, 9; so Sid. Carm. 23, 299.