SYN: Measurement, size, configuration, delineation, mass, bulk, extent.
ANT: Mismeasurement, segment.
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KEY: Dimidiate.
SYN: Halve, bisect.
ANT: Unite, integrate.
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KEY: Diminish.
SYN: Lessen, reduce, contract, curtail, dwarf, decrease, subside, shorten, abate, retrench.
ANT: Increase, enlarge, expand, extend, amplify, magnify.