Webster’s Revised Unabridged Dictionary · 1913
Rhythmic
Rhyth′mic (-mĭk), Rhyth′mic·al (- mĭ·kal), a. [Gr. ????: cf. L. rhythmicus, F. rhythmique.] Pertaining to, or of the nature of, rhythm
Day and night I worked my rhythmic thought. Mrs. Browning.
Rhythmical accent. (Mus.) See Accent, n., 6 (c).