Lighter: If you dial the dictionary back to Purcell's century you get this:

Celóma, the mariners-crye when they tug at a cable, weigh anker, or hoife-failes.
Celomare, to cry all together as mariners do, when they weigh anker or hoife-failes.
[Vocabulario Italiano & Inglese, Torriano, 1659]

The biblical definition leans toward "command." Which, I note, is often the first and last word spoken when chanting.

The only thing we're missing to meet the TikTok chanty basics is some late-19th century A&R.

A chanty is more than that but... so much more one can excuse the celeusma altogether from history? Or.... maybe you need to start over at the beginning now that you know what a celeusma is to begin with.