orth-

combining form

Definition of ORTH-

: straight : upright : vertical <orthograde>

: perpendicular <orthorhombic>

: correct : corrective <orthodontia>

a : hydrated or hydroxylated to the highest degree <orthophosphoric acid>

b : involving substitution at or characterized by or having the relationship of two neighboring positions in the benzene ring <ortho-xylene>

orth- or ortho-

Greek, from orthos straight, right, true; akin to Sanskrit ūrdhva high, upright

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