Correct spelling for the English word "sympexion" is [sˈɪmpɛkʃən], [sˈɪmpɛkʃən], [s_ˈɪ_m_p_ɛ_k_ʃ_ə_n] (IPA phonetic alphabet).
A concretion of nitrogenous matter in the seminal vesicles.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.