Correct spelling for the English word "ameristic" is [ˌaməɹˈɪstɪk], [ˌaməɹˈɪstɪk], [ˌa_m_ə_ɹ_ˈɪ_s_t_ɪ_k] (IPA phonetic alphabet).
Endowed with amerism, not dividing into parts or segments.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.