Entry 1 sense Webster, 1913 Peninsular /pən-ĭn'-səl-ẽr/ · Pen·in·su·lar · IPA /pəˈnɪn.sə.ləɹ/ 01 a. Of or pertaining to a peninsula; as, a peninsular form; peninsular people; the peninsular war. 1. Of or pertaining to a peninsula; as, a peninsular form; peninsular people; the peninsular war.