Definitions

1. pronoun

the object of a verb or preposition in a sentence, used as the object of a verb or preposition in the archaic second person singular

“Thou art thine, and thine art mine, and mine is thine, and thine is mine.”

2. noun

the person or people being addressed in the second person singular

“Thee, O Lord, I worship and adore.”

3. archaic

the person or people being addressed in the second person singular, used in poetry and formal writing

“Thee, fair maiden, I do implore.”