gregis
gregis is a Latin form of grex, meaning “flock, herd; band, crowd”. It is the genitive singular masculine noun.
Found 40 times in the Latin texts on Socratos.
Where it is used
Vergil, Eclogues 1.15: spem gregis, ah, silice in nuda conixa reliquit.
All forms of grex (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.