/ Dictionary / Index R roughing mill: Meaning and Definition of Find definitions for: rough'ing mill" Pronunciation: [key] — Metall. Metall. a rolling mill for converting steel ingots into blooms, billets, or slabs. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. roughing-in roughish Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language