Histri
Histri is a Latin form of Istrus, meaning “Istrian; (Hister) the Danube”. It is the nominative plural masculine adjective or vocative plural masculine adjective or genitive singular neuter adjective or genitive singular masculine adjective.
Found 27 times in the Latin texts on Socratos.
Where it is used
Ovid, Tristia 2.1.189: solus ad egressus missus septemplicis Histri
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.