USAGE: It is used with a hyphen: 1) to distinguish between a word in which the prefix means simply “again” or “anew” and a word of similar form having a special meaning or meanings [re-collect, recollect] 2) to avoid ambiguity in the formation of nonce words [re-urge] 3) esp. previously, before elements beginning with e [re-examine, now ... More @Wikipedia
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