Definition of thy in English:

thy

(also thine)

possessive determiner

  • ‘honour thy father and thy mother’
    archaic or dialect form of your
    • ‘If thou faint in the day of adversity, thy strength is small.’
    • ‘Come all ye people, offer thy assistance and ye may be greatly rewarded.’
    • ‘It is time to bid thee farewell, and let someone half thy hoary age step up and take thy place.’
    • ‘Deny thy father and refuse thy name; if thou wilt not, be but sworn by my love.’
    • ‘Come: thou hast now entered upon the wifehood Of this thy lord who takes thy hand and woos thee.’

Usage

The use of thy is still found in some traditional dialects but elsewhere it is restricted to archaic contexts. See also thou

Origin

Middle English thi (originally before words beginning with any consonant except h), reduced from thin, from Old English thīn (see thine).

Pronunciation

thy

/ðʌɪ/