Britannos
Britannos is a Latin form of Britannus, meaning “Britons (usu, pl.)”. It is the accusative plural masculine adjective.
Found 25 times in the Latin texts on Socratos.
Where it is used
Caesar, De Bello Gallico 4.21.5: Interim, consilio eius cognito et per mercatores perlato ad Britannos, a compluribus insulae civitatibus ad eum legati veniunt, qui polliceantur obsides dare atque imperio populi Romani obtemperare.
All forms of Britannus (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.