/ Thesaurus / B Synonyms of by the day Find synonyms for: Adverb1. per diem, by the dayusage: one every day; "we'll save 100 man-hours per diem"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language