Entry 1 sense Webster, 1913 Laudanum /lôd'-ən-əm/ · Lau·da·num · IPA /ˈlɔːdənəm/ 01 n. Tincture of opium, used for various medical purposes. 1. Tincture of opium, used for various medical purposes. Phrases & compounds Dutchman's laudanum — See under Dutchman.