Most distant from the center or inside; outmost.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "outermost" in a sentence
"Everyone is more or less of a fish than the capybara, defined as the outermost realm of fishdom by the 16th-century Catholic Church."
"The innermost planet is most probably rocky, while the outermost is the first Neptune-mass planet to reside in the habitable zone."
"On the point of the outermost is a crucifix, and between both, towards the middle, are figures of the Virgin"