The Proto-Indo-European word *h₁erh₁-
Word *h₁erh₁-
Meaning row
See also Proto-Indo-European: *h₁erh₁trom ‘oar, paddle’
Synonyms *wórghs

Comments
Mallory J.P. and Adams D. (2006)

Other words that might be of interest
*h₃enh₂- ‘contend, quarrel’