secret

Etymology

From Middle English secrette, from Old French secret, from Latin sēcrētus (“separated, hidden”), from ptp of sēcernō (“separate, to set aside, sunder out”), from cernō, from Proto-Indo-European *krey-. Displaced Old English dēagol (“secret”) and dēagolnes (“a secret”).

noun

1. (countable) A piece of knowledge that is hidden and intended to be kept hidden.
   "Can you keep a secret?" "Yes." "So can I."
   To tell our own secrets is generally folly, but that folly is without guilt; to communicate those with which we are intrusted is always treachery May 1, 1750, Samuel Johnson, The Rambler No. 13
   Barla Von: Most people think I deal in finances, but my real currency is knowledge. I trade information and it has made me very wealthy. Barla Von: But the Shadow Broker is the true master. Every day, he buys and sells secrets that could topple governments, always giving them to the highest bidder. 2008, BioWare, Mass Effect (Science Fiction), Redwood City: Electronic Arts, →OCLC, PC, scene: Citadel
   Now we are liberal with our innermost secrets, spraying them into the public ether with a generosity our forebears could not have imagined. Where we once sent love letters in a sealed envelope, or stuck photographs of our children in a family album, now such private material is despatched to servers and clouds operated by people we don't know and will never meet. 14 June 2013, Jonathan Freedland, “Obama's once hip brand is now tainted”, in The Guardian Weekly, volume 189, number 1, page 18
   The storage of cryptographic secrets is one of the paramount requirements in building trustworthy systems. 2014, Thomas Feller, Trustworthy Reconfigurable Systems
2. The key or principle by which something is made clear; the knack.
   The secret to a long-lasting marriage is compromise.
3. Something not understood or known.
4. (uncountable) Private seclusion.
   The work was done in secret, so that nobody could object.
5. (archaic, in the plural) The genital organs.
6. (historical) A form of steel skullcap.
7. (Christianity, often in the plural) Any prayer spoken inaudibly and not aloud; especially, one of the prayers in the Tridentine Mass, immediately following the "orate, fratres", said inaudibly by the celebrant.

adj

1. Being or kept hidden.
   We went down a secret passage.
2. (obsolete) Withdrawn from general intercourse or notice; in retirement or secrecy; secluded.
   secret in her sapphire cell 1716, Elijah Fenton, an ode to the Right Honourable John Lord Gower
3. (obsolete) Faithful to a secret; not inclined to divulge or betray confidence; secretive, separate, apart.
4. (obsolete) Separate; distinct.
   They suppose two other divine hypostases superior thereunto, which were perfectly secret from matter. 1678, Ralph Cudworth, The True Intellectual System of the Universe

verb

1. (transitive) To make or keep secret.
   … she would unfold the silk, press it with a smooth wooden block that she'd heated in the oven, and then once more secret it away. 1984, Peter Scott Lawrence, Around the mulberry tree, Firefly Books, p. 26
   1986, InfoWorld, InfoWorld Media Group, Inc. Diskless workstations … make it difficult for individuals to copy information … onto a diskette and secret it away.
   To prevent the elixir from reaching mankind and thereby upsetting the balance of the universe, two gods secret it away. 1994, Phyllis Granoff & Koichi Shinohara, Monks and magicians: religious biographies in Asia, Mosaic Press, p. 50
2. (transitive) To hide secretly.
   He was so scared for his safety he secreted arms around the house.