Longman Dictionary of Contemporary English - monday

~ n the day between Sunday and Tuesday. In Britain, Monday is considered the first day of the week, and in the US, it is considered the second day of the week  (It was raining on Monday. | I found it hard to get out of bed for work on Monday morning. | Sasha will arrive Monday. | on Mondays (=each Monday))  (We play football on Mondays. | a Monday (=one of the Mondays in a year))  (Does Christmas fall on a Monday this year?)