Dareum
Dareum is a Latin form of Dareus, meaning “Darius, name of Persian kings”. It is the genitive plural masculine noun or accusative singular masculine noun.
Found 61 times in the Latin texts on Socratos.
Where it is used
Cicero, Letters to his Friends 2.10.3: … victoria iusta imperator appellatus apud Issum, quo in loco, saepe ut ex te audivi, Clitarchus tibi narravit Dareum ab Alexandro esse superatum, abduxi exercitum ad infestissimam Ciliciae partem. ibi quintum et vicesimum iam …
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.