week 
/ˈwi:k/ noun
plural weeks /ˈwi:k/ noun 1 : a period of seven days ◊In the U.S., a week is usually considered to start on Sunday and end on Saturday, while in the U.K. a week is usually considered to start on Monday and end on Sunday. [count] ▪ the last week of the month ▪ I can meet you sometime next week. ▪ The menu changes each/every week. ▪ I volunteer at the school once a week. [=once every week] ▪ You can never be sure what will happen from one week to the next. [noncount] ▪ The menu changes from week to week. ▪ These problems have continued week after week. [=for several or many weeks] — see also holy week 2 [count] : any period of seven days in a row
▪ The baby is two weeks old. [a two-week-old baby] ▪ I'll be on vacation for two weeks starting this Tuesday. ▪ That car rents for $200 a/per week. ▪ We'll leave a week from today. [=seven days after today] ▪ I arrived a week ago. ▪ It took him two weeks to paint the house. ▪ Sometimes he's away for weeks at a time. ▪ The doctor said he wants to see me again in a week. = The doctor said he wants to see me again a week from now. = The doctor said he wants to see me again in a week's time. 3 [count] : the days from Monday through Friday when people usually work
▪ We're open from 9 to 5 all week. ▪ He earns $500 a week at his job. ▪ I'll be working next week. ▪ He has a 40-hour work week.
▪ The baby is two weeks old. [a two-week-old baby] ▪ I'll be on vacation for two weeks starting this Tuesday. ▪ That car rents for $200 a/per week. ▪ We'll leave a week from today. [=seven days after today] ▪ I arrived a week ago. ▪ It took him two weeks to paint the house. ▪ Sometimes he's away for weeks at a time. ▪ The doctor said he wants to see me again in a week. = The doctor said he wants to see me again a week from now. = The doctor said he wants to see me again in a week's time.
▪ We're open from 9 to 5 all week. ▪ He earns $500 a week at his job. ▪ I'll be working next week. ▪ He has a 40-hour work week.
week in and week out also week in, week out
: every week for many weeks : for a long time without stopping or changing
▪ He has been working week in and week out with no vacation.
▪ He has been working week in and week out with no vacation.
