pref.1. Straight; upright; vertical: orthotropous. 2. Perpendicular: orthorhombic. 3. Correct; correction: orthopsychiatry. 4. The most fully hydrated form of an acid or of its salts: orthoboric acid. 5. Of or relating to one of three possible isomers of a benzene ring with two attached chemical groups in which the carbon atoms with attached groups are adjacent: ortho-dibromobenzene.
[Middle English, from Old French, from Latin, from Greek, from orthos, straight, correct, right.] |