From hide. Concealed; put out of view; secret; not known; mysterious. Hidden fifths or octaves, consecutive fifths or octaves, not sounded, but suggested or implied in the parallel motion of two parts towards a fifth or an octave.
hidden may denote either known to on one; as, a hidden disease; or intentionally concealed; as, a hidden purpose of revenge. Secret denotes that the thing is known only to the party or parties concerned; as, a secret conspiracy. Covert literally denotes what is not open or avowed; as, a covert plan; but is often applied to what we mean shall be understood, without openly expressing it; as, a covert allusion. Secret is opposed to known, and hidden to revealed. Bring to light the hidden things of darkness. (1 cor. Iv. 5) My heart, which by a secret harmony still moves with thine, joined in connection sweet. (Milton) By what best way, Whether of open war, or covert guile, We now debate. (Milton)