/ ˌmɒdəˈreɪʃn; NAmE ˌmɑːd-/ noun [ U ]
1.
the quality of being reasonable and not being extreme :
There was a call for moderation on the part of the trade unions.
Alcohol should only ever be taken in moderation (= in small quantities) .
2.
( BrE ) ( in education ) the process of making sure that the same standards are used by different people in marking exams, etc.
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WORD ORIGIN
late Middle English : via Old French from Latin moderatio(n-) , from the verb moderare to control; related to modest .