What is the meaning of Thy?

Possessive form of thou: that which belongs to thee; which belongs to you .

Only used in for thy, for-thy, which is an alternative form of forthy (because, therefore)

Dialectal form of thyer

Alternative form of þi (thy)

Alternative form of þe (the)

Alternative form of þe (thee)

Alternative form of þei (they)

Alternative spelling of þy (the)

Alternative spelling of þy (thigh)

therefore, for that reason

thy, your

Source: wiktionary.org