The lyric from “Hark! The Herald Angels Sing” is “Glory to the newborn King,” so the stored answer is King.
The carol was written by Charles Wesley and first published in 1739 under the title “Hymn for Christmas-Day.” Its words draw on the biblical account of Christ’s birth, especially Luke 2:8–14, which describes angels announcing the nativity to shepherds.
The opening lines familiar today were not Wesley’s exact original wording. George Whitefield revised the first couplet in 1753, changing Wesley’s “Hark how all the welkin rings” to the better-known “Hark! the herald angels sing.” The phrase “newborn King” belongs to this widely sung revised form.
The melody also arrived later. Since the 19th century, the carol has usually been sung to music adapted by William H. Cummings from Felix Mendelssohn’s 1840 “Festgesang.” “Prince,” “Child,” and “Lord” fit the broader religious imagery of Christmas, but they do not complete this canonical line.