Lewis Short
(adjective) : paenultĭmus (pēn-), a, um, paene-ultimus
* The last but one (post-class. for proximus a postremo, Cic. Or. 64, 217): paenultima meta November,Aus. Ecl. Quotae Cal. Sint Mens. 12.
* Subst.: pae-nultĭma, ae, f. (sc. syllaba), the penultimate syllable, the penult: paenultimam circumflectere,Gell. 4, 7, 2.
Charlton T. Lewis, Charles Short, A Latin Dictionary