Defn: The property of cutting at right angles.

ORTHOTONE
Or"tho*tone, a. Etym: [Ortho- + Gr. (Gr. Gram.)

Defn: Retaining the accent; not enclitic; — said of certain indefinite pronouns and adverbs when used interrogatively, which, when not so used, are ordinarilly enclitic.

ORTHOTROPAL; ORTHOTROPOUS
Or*thot"ro*pal, Or*thot"ro*pous, a. Etym: [Ortho- + Gr. orthotrope.]
(Bot.)

Defn: Having the axis of an ovule or seed straight from the hilum and chalaza to the orifice or the micropyle; atropous.

Note: This word has also been used (but improperly) to describe any embryo whose radicle points towards, or is next to, the hilum.

ORTHOTROPIC
Or`tho*trop"ic, a. Etym: [See Orthotropal.] (Bot.)

Defn: Having the longer axis vertical; — said of erect stems. Encyc.
Brit.

ORTHOXYLENE
Or`tho*xy"lene, n. Etym: [Ortho- + xylene.] (Chem.)

Defn: That variety of xylene in which the two methyl groups are in the ortho position; a colorless, liquid, combustible hydrocarbon resembling benzene.