Used to indicate the one or ones belonging to thee.
Used instead of thy before an initial vowel or h: "The presidential candidates are practicing the first rule of warfare: know thine enemy” ( Eleanor Clift).
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.