Definition of mill-run in US English:

mill-run

noun

  • The material produced from a mill before sorting, especially the saleable output of a sawmill. In extended use: a person or thing regarded as average or mediocre.

adjective

  • Designating material produced from a mill before sorting, especially the saleable output of a sawmill. In extended use: lacking unusual or distinctive aspects; average, mundane, mediocre.

Origin

Mid 17th century (in an earlier sense). From mill + run.

Pronunciation

mill-run

/ˈmɪlrʌn/