D defs.my
Entry 1 sense Webster, 1913

Rhythmer

/(rĭth"mẽr [or] rĭt͟h"-)/ · Rhyth·mer · IPA /ˈɹɪðəmə(ɹ)/
01 n. One who writes in rhythm, esp. in poetic rhythm or meter.
  1. 1.
    One who writes in rhythm, esp. in poetic rhythm or meter.[R.]
    “One now scarce counted a rhythmer, formerly admitted for a poet.” Fuller.