As an adjective, it means not known, not identified, or not familiar. As a noun, it refers to something or someone that is not yet discovered or understood.
From Old English 'un-' (not) + 'cnāwan' (to know). The combined form 'unknown' has been used since at least the 1300s.
In math, the 'unknown' is the thing you’re solving for, like x. In life, the unknown is what scares us and also what makes discovery possible—it’s the blank space we get to fill.
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