A word or phrase placed typically before a substantive and indicating the relation of that substantive to a verb, an adjective, or another substantive, as English at, by, with, from, and in regard to.
To position or place in position in advance: artillery that was prepositioned at strategic points in the desert.
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.