TESTIS By N., Pam M.S. - April 29, 2013 noun. the primary reproductive organ in men, a couple of which are typically found within the scrotum. Commonly referred to as orchis. TESTIS: "Injury to the testis can render a male infertile." Related Psychology Terms OVARY ORCHIDECTOMY PHYLOGENY ALPHA MOTOR NEURON ARRESTED TESTIS AFTEREFFECT ORGAN LANGUAGE OVIDUCT TESTICLE POSTPARTUM PERIOD Cite this page: N., Pam M.S., "TESTIS," in PsychologyDictionary.org, April 29, 2013, https://psychologydictionary.org/testis/ (accessed October 19, 2020).