An Etymological Dictionary of the German Language/Annotated/Reim
Reim, masculine, ‘rhyme,’ from Middle High German rîm, masculine, ‘verse, line.’ To the assonant Old High German rîm, masculine, this sense is unknown; it signifies ‘row, succession, number,’ and these meanings are attached to the corresponding words in the other Old Teutonic dialects; compare Old Saxon unrîm, ‘innumerable quantity,’ Anglo-Saxon rîm, ‘number.’ From these Old Teutonic words Middle High German rîm, ‘verse,’ must be dissociated, and connected rather with Latin rhythmus (versus rhythmicus). The Modern High German word acquired the sense of French rîme, ‘rhyme,’ in the time of Opitz. In the Middle High German period rîme binden was used for reimen, ‘to rhyme,’ and Gebäude by the Meistersingers for Reim. English rhyme (Middle English rîme, ‘rhymed poem, poem, rhyme’) is also borrowed from Old French rime.