jo (n.)

c. 1200, "feeling of pleasure and delight;" c. 1300, "source of pleasure or happiness," from Old French joie "pleasure, delight, erotic pleasure, bliss, joyfulness" (11c.), from Latin gaudia "expressions of pleasure; sensual delight," plural of gaudium "joy, inward joy, gladness, delight; source of pleasure or delight," from gaudere "rejoice," from PIE root *gau- "to rejoice" (cognates: Greek gaio "I rejoice," Middle Irish guaire "noble").

As a term of endearment from 1580s. Joy-riding is American English, 1908; joy-ride (n.) is from 1909.