Lewis & Short

hĕcătombē, ēs, f., = ἑκατόμβη, a great sacrifice of a hundred oxen, a hecatomb (ante- and post-class.): facere hecatomben, Varr. ap. Non. 131, 19; Juv. 12, 101 al.
In plur.: celebratis hecatombis, Treb. Gall. 9.
Dim. hĕcătombĭon, ii, n., Sid. Carm. 9, 205.