Grammar Point
particle
prt 
を

indicates time (period) over which action takes place

Noun (Time Period) + を + Verb

The particle を is used to indicate a period of time over which an action or state persists. It emphasizes the passage of time or the act of 'spending' that specific duration performing an activity.

Spending or passing a duration

In this context, を marks the time frame that the subject 'moves through.' It is frequently used with verbs like 過ごす (to spend time), 経る (to pass/elapse), or verbs indicating a continuous state.

To spend a happy time.

A week passes / goes by.

To end/finish the day.

Note

This usage is semantically linked to the 'space/path' を. Just as you move through physical space, you are 'moving through' a segment of time. It is distinct from に (which marks a specific point in time) or まで (which marks a deadline).

Words: 
を
Radicals of radicals