Entry 1 sense Webster, 1913 Pentecostal /pĕnˌ-tək-ôs'-təl/ · Pen·te·cos·tal · IPA /ˌpen.tɪˈkɒs.təl/ 01 a. Of or pertaining to Pentecost or to Whitsuntide. 1. Of or pertaining to Pentecost or to Whitsuntide.