herm, n.All

A Herm (n.) was ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠a statue of Mercurius with a hidden image of the god inside, so the plain figure housed the real one, like the Silenus figures Alcibiades compared to Socrates.