Is joy to the world in ternary form?

Yes, "Joy to the World" is in ternary form. Ternary form, also known as ABA form, is a musical structure consisting of three sections: the first section (A), the second section (B), and the third section (A'), which is a repetition of the first section. "Joy to the World" follows this structure, with the first section being the main theme of the song, the second section being a contrasting section, and the third section being a repetition of the main theme.