rerum
rerum is a Latin form of res, meaning “thing, matter, affair; fact; property”. It is the genitive plural feminine noun.
Found 3,624 times in the Latin texts on Socratos.
Where it is used
Caesar, De Bello Gallico 1.14.5: Consuesse enim deos immortales, quo gravius homines ex commutatione rerum doleant, quos pro scelere eorum ulcisci velint, his secundiores interdum res et diuturniorem impunitatem concedere.
Cicero, In C. Verrem 2.5.56: … ab his tamen exigis. cedo mihi eiusdem praetoris litteras et rerum decretarum et frumenti imperati. litterae rervm decretarvm. Quid potius in hac tanta et tam turpi inconstantia suspicari possumus, iudices, quam id quod nece …
Suetonius, Divus Claudius 23.1: Rerum actum diuisum antea in hibernos aestiuosque menses coniunxit. iuris dictionem de fidei commissis quotannis et …
All forms of res (declension table)
Source: Socratos (socratos.org), a free reader for Ancient Greek and Latin. Grammar from the Perseus Treebank and Morpheus; dictionary entries from Lewis & Short, A Latin Dictionary (Perseus Digital Library, CC BY-SA). Counts are from the texts on Socratos.