crypto-, crypt-

(Greek: hidden, secret, secrets, secret writing; by extension, applied to secret code or ciphers)

telecryptograph (s) (noun), telecryptographs (pl)
A form of printing telegraph messages that is adopted so it prints secret or private communications.
trichocryptosis (s) (noun), trichocryptoses (pl)
Any disease of the hair follicles: Trichocryptosis is a term used to describe all kinds of infections, disorders, or ailments of the hair follicles.
xylocryptite (s) (noun), xylocryptites (pl)
Something that is hidden in fossil wood.

A cross reference of other word family units that are related directly, or indirectly, to: "secret, hidden, confidential, concealed": ceal-; clandesti-; myster-; occult-; orgy; stego-, stegano-.