nou·me·non (nōō'mə-nŏn') n.
pl.nou·me·na (-nə) In the philosophy of Kant, an object as it is in itself independent of the mind, as opposed to a phenomenon. Also called thing-in-itself.
[German, from Greek nooumenon, from neuter present passive participle of noein, to perceive by thought, from nous, mind.] nou'men·al (-mə-nəl) adj.