In re

In re, Latin for "in the matter [of]", is a term with several different, but related meanings.

In correspondence, the phrase in re: refers to the subject of a letter, memorandum, or electronic mail message. It is used especially in e-mail to denote in regard to; confusingly, RE: is employed to mean in reply to:.

In jurisprudence, in re: is used to indicate that a judicial proceeding may not have formally designated adverse parties or is otherwise uncontested. The term is commonly used in case citations of probate and bankruptcy proceedings, for example, In re Marriage Cases and General Motors Chapter 11 reorganization; it is also used in juvenile courts, as, for instance, In re Gault.

In philosophy, in re means in reality, a statement about the real world as oppose to a statement about an ideal world - Plato's idea of philosopher kings, for example, has been criticized for being impossible to maintain in re.

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