The Latin phrase sub rosa (Neo-Latin for "under the rose") denotes secrecy or confidentiality and is used in English to denote secrecy or confidentiality; this is somewhat in contrast to the Chatham House Rule which is an enforcement of non-attribution rather than secrecy. The rose has a long, ancient history as a symbol of secrecy.

The rose has held a deeply symbolic significance in many times and cultures as a symbol of maternal creativity and of the yoni or feminine generative power.^{[1][unreliable source?]} The literal rose and its essence or attar has also played a role in religious and spiritual rites which ofttimes would have been held in secret.^{[2][unreliable source?]}

The rose has sometimes been said to have been the emblem of the god Horus in ancient Egypt; however, the gods in Egypt were usually associated with the lotus. The idea of Horus being linked to the rose probably arises from Greek and Roman cultural cross-transmission of myths from Egypt. Firstly, the rose's connotation with secrecy dates back also to Greek mythology. In Hellenistic and later Roman mythology, Aphrodite/Venus gave a rose to her son, Eros/Cupid (the god of love), who, in turn, gave it to Harpocrates, the god of silence (and a Greek name for a form of Horus), to ensure that his mother's indiscretions (or those of the gods in general, in other accounts) were not disclosed.^[3] Secondly, in Egypt, the rose was actually sacred to Isis, but this appears to have been during the Roman period of Egyptian history: "Probably due to assimilation with the goddess Aphrodite (Venus), during the Roman period, the rose was used in her worship."^{[citation needed]}

Later, the Greeks and Romans translated the god's Egyptian name Heru-pa-khered as Harpocrates and regarded him as the god of silence. The association of Harpocrates with silence and secrecy originates from a misunderstanding of Egyptian depictions of the god. Heru-pa-khered was represented as a naked youth with a finger-to-mouth gesture—in Egyptian artwork this gesture imitates the hieroglyph for child and is used to represent youth, but was misunderstood by Greeks and Romans as a gesture for silence.^{[citation needed]}

Paintings of roses on the ceilings of Roman banquet rooms were also a reminder that things said under the influence of wine (sub vino) should also remain sub rosa.^[4]

In the Middle Ages a rose suspended from the ceiling of a council chamber similarly pledged all present (those under the rose) to secrecy.^[5]

In Christian symbolism, inherited from older roots, the phrase "sub rosa" has a special place in confessions, where roses were carved on confessionals to signify that the conversations would remain secret.^[3] Pictures of five-petalled roses were often carved on confessionals, indicating that the conversations would remain secret.^[3] The phrase has also been understood to refer to the mysterious virginal conception of Christ.

The rose is also an esoteric symbol of Rosicrucianism which was often considered to be a secret society or brotherhood.

In the 16th century, the symbol of Henry VII of England was the stylised Tudor dynasty rose. A large image of the rose covered the ceiling of the private chamber where decisions of state were made in secret.^{[citation needed]}

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.^[3]

In current times, the term is used by the Scottish Government for a specific series of "off the record" meetings.^[5]

• Language of flowers
• Chatham House Rule