What is Secret?

Legal Definition
Rights. A knowledge of something which is unknown to orthers, out of which a profit may be made; for example, an invention of a machine, or the discovery of the effect of the combination of certain matters.

2. Instances have occurred of secrets of that kind being kept for many years, but they are liable to constant detection. As such secrets are not pro-perty, the possessors of them in general prefer making them public, and securing the exclusive right for years, under the patent laws, to keeping them in an insecure manner, without them. See Phil. on Pat. ch. 15; Gods. on Pat. 171; Dav. Pat. Cas. 429; 8 Ves. 215; 2 Ves. & B. 218; 2 Mer. 446; 3 Mer. 157; 1 Jac. & W. 394; 1 Pick. 443; 4 Mason, 15; 3 B. & P. 630.
-- Bouviers Law Dictionary
Legal Definition
Concealed; hidden; not made public; particularly, in law, kept from the knowledge or notice of persons liable to be affected by the act, transaction, deed or other thing spoken of. As to secret "Committee," "Equity," "Lien," "Partnership," and "Trust," see those titles.
-- Black's Law Dictionary