the margin required in order to insure safety; "in engineering the margin of safety is the strength of the material minus the anticipated stress" 同義詞:margin of safety, safety margin
The margin of error is a statistic expressing the amount of random sampling error in a survey's results. The larger the margin of error, the less confidence one should have that the poll's reported results are close to the "true" figures; that is, the figures for the whole population.