ortho

adjective

or·​tho ˈȯr-(ˌ)thō 

: orthochromatic

Word History

First Known Use

1904, in the meaning defined above

Medical Definition

ortho

1 of 2 adjective

or·​tho ˈȯr-(ˌ)thō 

1

: derived from or being an acid in the highest hydrated or hydroxylated form known

2

: relating to, characterized by, or being two neighboring positions in the benzene ring

ortho

2 of 2 adjective

: orthochromatic