Of course, Tuesdays is also the plural of Tuesday, the name of the workday that falls between Monday and Wednesday. Tuesdays, when used as an adverb, denotes when something happens or when an action is performed. Saying "I work Tuesdays," for example, indicates that you work every Tuesday. Tuesdays is also the correct spelling for the noun form of the word. When you write about something called "a Tuesday night," for example, you are referring to a night that falls on a Tuesday. Finally, Thursdays is the correct spelling for the adjective form of the word. If you call something "a Thursday delivery," for example, you are indicating that it arrives at its destination on that day.