Correct spelling for the English word "estoral" is [ˈɛstəɹə͡l], [ˈɛstəɹəl], [ˈɛ_s_t_ə_ɹ_əl] (IPA phonetic alphabet).
Boric-acid menthol ester, a colorless crystalline powder, employed as an errhine in chronic nasal catarrh.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.