- septentrion (n.)
- "the Big Dipper;" Middle English septentrioun (1530s, but septentronial "northern" is attested from late 14c.), from Latin septentriones (plural) "seven plow oxen," from septem "seven" + trio (genitive triones) "plow ox," from stem of terere (pt. tritus) "to rub" (see throw). Cf. also Charles's Wain.