Defn: A variety of allanite occurring in slender prismatic crystals.
ORTHO-
Or"tho-. Etym: [Gr. upright, vrdh to grow, to cause to grow.]
1. A combining form signifying straight, right, upright, correct, regular; as, orthodromy, orthodiagonal, orthodox, orthographic.
2. (Chem.)
Defn: A combining form (also used adjectively), designating: (a) (Inorganic Chem.) The one of several acids of the same element (as the phosphoric acids), which actually occurs with the greatest number of hydroxyl groups; as, orthophosphoric acid. Cf. Normal. (b) (Organic Chem.)
Defn: Connection with, or affinity to, one variety of isomerism, characteristic of the benzene compounds; — contrasted with meta- or para-; as, the ortho position; hence, designating any substance showing such isomerism; as, an ortho compound.
Note: In the graphic representation of the benzene nucleus (see Benzene nucleus, under Benzene), provisionally adopted, any substance exhibiting double substitution in adjacent and contiguous carbon atoms, as 1 & 2, 3 & 4, 4 & 5, etc., is designated by ortho-; as, orthoxylene; any substance exhibiting substitution of two carbon atoms with one intervening, as 1 & 3, 2 & 4, 3 & 5, 4 & 6, etc., by meta-; as, resorcin or metaxylene; any substance exhibiting substitution in opposite parts, as 1 & 4, 2 & 5, 3 & 6, by para-; as, hydroquinone or paraxylene.
ORTHOCARBONIC
Or`tho*car*bon"ic, a. Etym: [Ortho- + carbonic.] (Chem.)
Defn: Designating a complex ether, C.(OC2H5)4, which is obtained as a liquid of a pleasant ethereal odor by means of chlorpicrin, and is believed to be a derivative of the hypothetical normal carbonic acid, C.(OH)4.
ORTHOCENTER
Or`tho*cen"ter, n. Etym: [Ortho- + center.] (Geom.)