Lewis Short
(adjective) : bētācĕus, a, um, 1. beta
* From or of the beet: pedes betacei,beet-roots,Varr. R. R. 1, 2, 27.—Subst.: bētācĕus, i, m. (sc. pes), beet-root (cf. Charis. pp. 24 and 128 P.; Prisc. p. 618 ib.), Apic. 3, 2; Plin. Ep. 1, 15, 2 (where others, less correctly, read Baeticae); Arn. 4, p. 133 (others, betis).
Charlton T. Lewis, Charles Short, A Latin Dictionary