south-ˈeasternmost,a. [f. south-eastern a. + -most.] Lying furthest to the south-east. 1837Penny Cycl. VIII. 398/1 A range of hills..runs from the north-easternmost point to the south-easternmost at Svenborg.1845J. Coulter Adv. in Pacific xvii. 278 The south-easternmost part of Tahiti.