orthodromie, n.f., orthodromy.
orthoépie, n.f., orthoëpy.
orthogonal, -e, adj., orthogonal.
orthogonalement, adv., in a right angle.
orthogone, adj., (geom.) orthogonal.
orthographe, n.f., orthography, spelling. Faute d’—; mistake in spelling.
orthographie, n.f., (arch., bot., geom., persp.) orthography.
orthographier, v.a. and n., to spell.
orthographique, adj., orthographical, orthographic. Dessin —; orthographical drawing.
orthographiste, n.m., orthographer.