# ortho-

> English word · Prefix · IPA /ɔː.θə-/

## Definitions
1. Right angle, perpendicular.
2. Proper, righteous, pure.
3. To correct or fix.
4. Same, from the same.
5. Normal, ordinary.
6. Straight in form.
7. Orthorhombic crystal structure.
8. In isomeric benzene derivatives, having the two substituents in adjacent (1,2) positions (compare meta- and para-).
9. Having an extra proportion of water.
10. Independent, separate.
11. Original, primary.
12. Parallel lines or columns.
13. Of any molecule of the form X₂ in which the two nuclei have parallel spin.
14. Orthopaedics.
15. Vertical or upright in movement.
16. Igneous.

## Etymology
Learned borrowing from Ancient Greek ὀρθός (orthós).

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-09-03.
Canonical page: https://plainspell.com/en/word/ortho