(1) In a state of continuous unremitting action; denoting especially a prolonged muscular contraction. (2) Invigorating; increasing physical or mental tone or strength. (3) A remedy purported to restore enfeebled function and promote vigor and a sense of well-being; tonics are qualified, according to the organ or system on which they are presumed to act, as cardiac, digestive, hematic, vascular, nerve, uterine, general, etc. [G. tonikos, fr. tonos, tone]