Entry 1 sense Webster, 1913 Testicle /tĕsʹtĭ-kəl/ · Tes·ti·cle · IPA /ˈtɛstɪkəl/ 01 n. One of the essential male genital glands which secrete the semen. 1. One of the essential male genital glands which secrete the semen.(Anat.)