RHYOLITE
Rhy"o*lite, n. Etym: [Gr. -lite.] (Min.)

Defn: A quartzose trachyte, an igneous rock often showing a fluidal
structure.
— Rhy`o*lit"ic, a.

RHYPAROGRAPHY Rhy`pa*rog"ra*phy, n. Etym: [Gr. "ryparo`s filthy, dirty + gra`fein to write, paint.]

Defn: In ancient art, the painting of genre or still-life pictures.

RHYSIMETER
Rhy*sim"e*ter, n. Etym: [Gr. -meter.]

Defn: An instrument, acting on the principle of Pitot's tube, for measuring the velocity of a fluid current, the speed of a ship, etc.

RHYTHM
Rhythm, n. Etym: [F. rhythme, rythme, L. rhythmus, fr. GR. Stream.]

1. In the widest sense, a dividing into short portions by a regular succession of motions, impulses, sounds, accents, etc., producing an agreeable effect, as in music poetry, the dance, or the like.

2. (Mus.)

Defn: Movement in musical time, with periodical recurrence of accent; the measured beat or pulse which marks the character and expression of the music; symmetry of movement and accent. Moore (Encyc. )