The Proto-Indo-European word *hₐértus
Word *hₐértus
Meaning order, fitting
See also Proto-Indo-European: *hₐer- ‘to put together, to prepare’
Synonyms *yéw(e)s-

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

Other words that might be of interest
*bak- ‘club’, *lorgehₐ- ‘club’