my 
(mī)
(mī)adj. The possessive form of I1.
1. Used as a modifier before a noun: my boots; my accomplishments.
2. Used preceding various forms of polite, affectionate, or familiar address: My friend, you are so right.
3. Used in various interjectional phrases: My word! My goodness!
interj.
Used as an exclamation of surprise, pleasure, or dismay: Oh, my! What a tiring day!
[Middle English mi, from Old English mīn; see me-1 in the Appendix of Indo-European roots. Interj., short for My God!.]