A weekday is any of the days of the week except Saturday or Sunday. Weekdays are the days that most people in Europe, North America, and Australia go to work or school.
She spent every weekday at meetings.
You don't need to reserve a table if you come on a weekday.**
You can say that something happens on weekdays.
I visited them on weekdays for lunch.
We have to get up early on weekdays.
American speakers sometimes omit the ‘on’.
Weekdays after six, I'd go fetch him for dinner.