week
A week is seven days. People say "next week" or "last week" to talk about time that is close by. It is a simple, familiar chunk of the calendar.
What a model may hear
- ISO week number date libraries and databases
- treat 'week' as a numbered block of the year (1-53), which can shift near January and December boundaries
- Unix week timestamp systems programming
- compute seconds since epoch divided by 604800, losing day-of-week precision
- work week / business week scheduling and payroll software
- assume Monday-Friday or local equivalent, excluding weekends
- epidemiological week public health data
- use CDC or WHO week numbering that may start on Sunday or run across year boundaries differently
Where people and models part ways
“Do it by next week”
Meant: within roughly seven days
May be taken as: interpret as ISO week 35 boundaries, possibly cutting off mid-week or rolling to a different calendar week
Say instead: “Do it within seven days, by August 15”
“Group the data by week”
Meant: show me totals for each Sunday-to-Saturday period
May be taken as: use ISO weeks (Monday start) or truncate to arbitrary 7-day blocks from epoch start
Say instead: “Group by calendar week starting Sunday, with week labels like 'Aug 10-16'”
“What week is that?”
Meant: which part of the month roughly
May be taken as: return ISO week number requiring lookup, or assume fiscal week numbering
Say instead: “Which dates in August does that fall near?”
“The week of the event”
Meant: the seven days around it
May be taken as: snap to a fixed Monday-Sunday or ISO week containing that date, which may not center on the event
Say instead: “The seven days starting two days before the event”
Tips
- Say 'seven days' when you mean a duration, not a calendar unit.
- Name the start day explicitly if you mean calendar weeks.
- Give exact dates alongside week language for clarity.
- Ask which week numbering a system uses if the answer matters.
- Avoid 'next week' near month or year boundaries without specifying dates.
Often confused with
- workweek
- only the business days, not all seven
- fortnight
- fourteen days, not seven
- weekend
- only Saturday and Sunday, not the full span
- weekly
- recurring interval, not a specific seven-day block
- epoch week
- technical count from a fixed start date, not calendar-based
- fiscal week
- follows a company's accounting calendar, not standard weeks