day
n. countablen. the period of 24 hours from one midnight to the next. It can also mean the time when it is light outside before the sun goes down.
n. a period of twenty-four hours, representing one full rotation of the Earth on its axis. It also refers to the interval between sunrise and sunset.
I work five days a week.
The shortest day of the year occurs in December for people living in the northern hemisphere.
While a solar day lasts exactly twenty-four hours, a sidereal day is slightly shorter because it measures Earth's rotation relative to the distant stars rather than the sun.
Commonly used with the preposition 'on' for specific dates and 'in' for general periods.
I will see you in MondayI will see you on MondayEnglish uses the preposition 'on' for specific days of the week.