ortho

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ortho-

(word root) straightExamples of words with the root ortho-: orthodontia

or·tho

O0128300 (ôr′thō)adj. Orthochromatic.

[From ortho-.]

or•tho

(ˈɔr θoʊ)

adj. pertaining to or occupying two adjacent positions in the benzene ring. Compare meta, para ². [1875–80; independent use of ortho-]

ortho-

1. a combining form meaning “straight,” “upright,” “right,” “correct”: orthodontics; orthopedic. 2. a. a combining form used in the name of the most hydrated acid in a given series: orthoboric acid. Compare meta- (def. 2a), pyro- (def. 2a). b. a combining form used in the names of benzene derivatives in which the substituting group occupies the ortho position in the benzene ring. Also, esp. before a vowel, orth-. [< Greek, comb. form of orthós straight, upright, correct]

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ORTHO