Entry 1 sense Webster, 1913 Lamarckian /lə-mär'kē-ən/ · La·marck·i·an · IPA /ləˈmɑɹki.ən/ 01 a. Pertaining to, or involved in, the doctrines of Lamarckianism. 1. Pertaining to, or involved in, the doctrines of Lamarckianism.