Prefixes are small but meaningful letter groups added before a base word or root that change the root’s meaning. Learning the meaning of these word parts, together with the meaning of common base words and Greek and Latin roots, gives readers the key for unlocking the meanings of hundreds of words.

Examples of prefixes that have to do with negation and reversal:

a- ahistoric, amoral, apolitical, asymmetry, asymmetrical, atypical

de- decaffeinated, defrost, defuse, demerit, deregulate, destabilize

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