The Oxford English Dictionary calls "celeusma" "Obsolete" and "rare" in English.

It is defined as "A watchword, battle-cry; the call of the signalman who gives the time to rowers."

Adams's "Compendious Dictionary of the Latin Tongue" (1805) defines it as "the musical cry, by which seamen incited one another to ply their oars."

A "call" or "musical cry."

Something of a regularly shouted command in the former case and a "sing-out" in the latter.

Hardly a chantey in the 19th century sense.