Plural of calliope; multiple steam organs or mechanical musical instruments with whistles, or references to the Greek muse Calliope.
From Calliope the muse, the instrument was named 'calliope' because of the dramatic, piercing tones of its whistles. The plural '-es' is standard for words ending in '-e'.
Carnival calliopes—those wild steam organs with their screaming whistles—were named after a Greek muse, so every time a carnival played one, they were theoretically channeling the spirit of epic poetry through noise.
Complete word intelligence in one call. Free tier — 50 lookups/day.