Entry 1 sense Webster, 1913 Petersham /(pē"tẽr*shăm)/ · Pe·ter·sham · IPA /ˈpiːtəʃəm/ 01 n. A rough, knotted woolen cloth, used chiefly for men's overcoats; also, a coat of that material. 1. A rough, knotted woolen cloth, used chiefly for men's overcoats; also, a coat of that material.