<p><strong>Adjective</strong></p><ul><li>not known; not within the range of one's knowledge, experience, or understanding; strange; unfamiliar.</li><li>not discovered, explored, identified, or ascertained: the unknown parts of Antarctica.</li><li>not widely known; not famous; obscure: an unknown writer.</li></ul><p><strong>Noun</strong></p><ul><li>a thing, influence, area, factor, or person that is unknown: the many unknowns in modern medicine; The director cast an unknown in the leading role.</li><li>Mathematics. a symbol representing an unknown quantity: in algebra, analysis, etc., frequently represented by a letter from the last part of the alphabet, as x, y, or z.</li></ul><p><strong>End of Response</strong></p>