septentriˈonic,a.rare. In quot.septem-. [f. L. septentrio Septentrion + -ic.] Northern. 1844Fraser's Mag. XXX. 318/2 The minstrelsie of our septemtrionic tubes was made applicable to classic themes. So septentriˈonicala.rare. 1654Gayton Pleas. Notes iv. vi–vii. 203 The septentrionicall part of those Saxons.