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asymmetrical (adj.)[asymmetrical 词源字典]: 1680s; see asymmetry + -ical. Other forms that have served as an adjective based on asymmetry are asymmetral (1620s), asymmetrous (1660s), and asymmetric (1875); only the last seems to have any currency. Related: Asymmetrically.[asymmetrical etymology, asymmetrical origin, 英语词源]
symmetrical (adj.): 1751, from symmetry + -ical. Related: Symmetrically (1570s).
well-rounded (adj.): 1796, "symmetrically proportioned, complete in all parts," from well (adv.) + past participle of round (v.). Figurative sense is from mid-19c.