Having multiple flat surfaces or faces; showing many different sides or aspects of something.
From 'facet' (from French 'facette', diminutive of 'face', meaning small face), plus '-ed' past participle. Originally a jeweler's term that became metaphorical.
A diamond's brilliance comes from being 'faceted'—cutting flat surfaces at angles so light bounces around inside—which is why we use the word metaphorically for people with 'many facets' to their personality, like a brilliant gem!
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