sub rosa
History
In Hellenistic and later Roman mythology, roses were associated with secrecy because Cupid gave a rose to Harpocrates (the Hellenistic god of silence) so that he would not reveal the secrets of Venus.{{cite web|work=Merriam-Webster.com Dictionary|url=https://www.merriam-webster.com/dictionary/sub-rosa|title=sub rosa|access-date=February 6, 2021}} Banquet rooms were decorated with rose carvings, reportedly as a reminder that discussions in the rooms should be kept in confidence.
This was inherited in later Christian symbolism, where roses were carved on confessionals to signify that the conversations would remain secret.
The phrase entered the German language (unter der Rose) and, later, the English language, both as a Latin loan phrase (at least as early as 1654) and in its English translation.
See also
{{Wiktionary|sub rosa|under the rose}}