A clinical study in ClinicalTrials.gov with a status of Recruiting; Not yet recruiting; or Active, not recruiting and whose status has not been confirmed within the past 2 years. Studies with an Unkno [..]

c. 1300, "strange, unfamiliar" (of persons, places), from un- (1) "not" + past participle of know (v.). Compare Old English ungecnawen. In reference to facts, "not discovered [..]

a number we do not know. • a variable representing an unknown quantity.

not known; "an unknown amount"; "an unknown island"; "an unknown writer"; "an unknown source" na [..]

umbakant

To dream of meeting unknown persons, foretells change for good, or bad as the person is good looking, or ugly, or deformed. To feel that you are unknown, denotes that strange things will cast a shadow of ill luck over you. See Mystery.   

(n) an unknown and unexplored region(n) anyone who does not belong in the environment in which they are found(n) a variable whose values are solutions of an equation(adj) not known(adj) being or havin [..]

incognitus, incompertus, ignotus

The Great Unknown. Sir Walter Scott. So called because the Waverley Novels were at first published anonymously. It was James Ballantyne who first applied the term to the unknown novelist.