Entry 1 sense Webster, 1913 Luminescent /lo͞omˌ-ən-ĕs'-ənt/ · Lu·mi·nes·cent · IPA /luːmɪˈnɛs(ə)nt/ 01 a. Shining with a light due to any of the various causes which produce luminescence. 1. Shining with a light due to any of the various causes which produce luminescence.(Physics)