Lewis Short
(adjective) : pōmĕrīdĭānus (postm-), a, um, post-meridianus
* In the afternoon, post-meridian: impetratum est a consuetudine, ut peccare suavitatis causā liceret, et pomeridianus quadrigas quam postmeridianus libentius dixerim,Cic. Or. 47, 157: pomeridianum tempus,id. de Or. 3, 5, 17; also: postmeridianum tempus,id. Tusc. 3, 3, 7: dies,Sen. Ep. 7, 3, 1: horae,Suet. Gram. 24: gnomonis umbra,Vitr. 1, 6: pomeridiana sessio (opp. ambulatio antemeridiana),Cic. de Or. 3, 30, 121: litterae,id. Att. 12, 53 fin.
Charlton T. Lewis, Charles Short, A Latin Dictionary