The Collaborative International Dictionary
Oblongum
Oblongum \Ob*lon"gum\, n.; pl. Oblonga. [NL. See Oblong.] (Geom.) A prolate spheroid; a figure described by the revolution of an ellipse about its greater axis. Cf. Oblatum, and see Ellipsoid of revolution, under Ellipsoid.
Wiktionary
oblongum
n. (context geometry archaic English) A prolate spheroid; a figure described by the revolution of an ellipse about its greater axis.