cătōnĭum, ii, n. [κάτω],
the Lower World , Laber. ap. Gell. 16, 7, 4; cf. Schol. Juv. p. 65 Cram.—Hence the play upon the word: vereor, ne in catonium Catoninos, Cic. Fam. 7, 25, 1 B. and K. (others read catomum; v. this word).
catōnium ī, n κάτω, the lower world (in a play on the name Cato). ...
An Elementary Latin Dictionary