Monday /ˈmʌn.deɪ/noun 1adverb 1forms 1phrases 1 noun1 •the day of the week between Sunday and TuesdayMr. Whymper, a solicitor living in Willingdon, […] would visit the farm every Monday morning to receive his instructions. — 1943 adverb1 •(US, Canada) On Monday.We've worked out the schedule for Easter week: we'll be shopping Monday. formsMondays Phrases with Monday Monday-morning quarterbackSomeone who criticizes with hindsight.