Source : Webster's Revised Unabridged Dictionary (1913)

Testicle \Tes"ti*cle\, n. [L. testiculus, dim. of testis a
   testicle, probably the same word as testis a witness, as
   being a witness to manhood. Cf. {Test} a witness.] (Anat.)
   One of the essential male genital glands which secrete the
   semen.

Source : WordNet®

testicle
     n : one of the two male reproductive glands that produce
         spermatozoa and secrete androgens; "she kicked him in the
         balls and got away" [syn: {testis}, {orchis}, {ball}, {ballock},
          {bollock}, {nut}, {egg}]