natural (adj)
Sens 1 : of, concerned with or produced by nature, not by human beings. [source : OAL]
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Sens 2 : belonging to, operating, or taking place in, the physical
(as opposed to the spiritual or intellectual) world. [source : OED]
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Sens 3 : of a substance or article: not manufactured or processed;
not obtained by artificial processes; made only from natural products. [source : D'après OED]