not contaminated; gnotobiotic: said esp. of a culture medium devoid of all living organisms except those of a single species
See axenic in American Heritage Dictionary 4
(ā-zĕnˈĭk, ā-zēˈnĭk)
adjective
Not contaminated by or associated with any other living organisms. Usually used in reference to pure cultures of microorganisms that are completely free of the presence of other organisms.