In English hymnody tunes are given names independently of the words. This is because they were usually written separately & mixing and matching words and tunes of the same meter was expected.

Sometimes a set of words becomes tied so completly to one tune that alterations just don't seem right, but there's always a possibility of new words to an old tune or a new tune for old words.

There are dozens of tunes used with While Shepherd's Watched Thier Flocks by Night. People could not just say let's sing it, they'd have to specify which tune.

Just look at the first page of the 1st line index of the Sacred Harp and see how many times "All hail the power of Jesus Name" or "Am I a Soldier of the Cross are used."

Tune names themselves are a combination of names meaningful to the composer or just picked up along the was. Coronation really was written to go with "All Hail the Power..." with the last line "Crown him lord of all" so the name makes sense. Many are geographical references, perhaps written for a special event or singing school held there. Nehemiah Shumway lived in eastern New York & wrote tunes with the names Schenectady & Ballstown (both near Albany). Some of the tunes in Sacred Harp are named for friends of the composer. Timothy Swan, who wrote China, also wrote one called Poland so I guess he liked using country names.

If you dig around in books enough, you can find the same tune with different names or the same name for different tunes. Sacred Harp has 2 Jordans & 3 Parting Friends. Greefields mentioned by UJ is also call Contrast. Sacred Harp has a tune called Sacred Throne, which fits the words in the book, but most hymnals call it Avon or Martyrdom and use it with "Alas an did my Saviour bleed."

The Shape Note books really were written as tune books with a set of words given, but only as a suggestion as to what words worked. Because they were produced to convey the music the title of the tune is given pride of place. You will find the tune names in more ordinary hymnals, it's just that they are placing the emphasis on the words so the first line usually becomes the title. There were many books published with just words.

This system began to break down during the 19th cent. as more & more hymnals were published with music & all the verses meant to be sung. With the development of gospel songs in the late 19th cent. the word & tune writing became much more tightly linked so it's hard to imagine mixing & matching the way it was done earlier.