Hour (h)
Definition: An hour is a unit of time equal to 60 minutes, or 3,600 seconds.
History/origin: The 24-hour day traces back to ancient civilizations, especially Egyptian and Babylonian systems, and became standard in civil timekeeping.
Current use: Hours are used for work schedules, travel time, time tracking, business operations, and daily planning.
Week (wk)
Definition: The week is a calendar interval of seven days, commonly used to group work, school, religious, and planning cycles.
History/origin: Seven-day cycles spread through ancient religious, astronomical, and civic traditions before becoming embedded in modern international calendars.
Current use: Wk is common in work schedules, class plans, sprint planning, pregnancy tracking, subscriptions, recurring chores, rent cycles, and short-term goals.