MY, pronoun. adj. contracted from migen, mine. Me was originally mig, and the adjective migen. So in L. meus. See Mine.

Belonging to me as, this is my book. Formerly, mine was used before a vowel, and my before a consonant my is now used before both. We say, my book my own book my old friend. Mine is still used after a verb as, this book is mine.