cornu
cornu is a wind instrument.
Also recorded as cornum.
Overview
Ancient Roman brass instrument.
In detail
Its recorded use is military communications.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“Cornu (horn)”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q1134287: cornu
Consult the source