This is the 414th most frequent Romanian word.
marţi
"Marţi" means "Tuesday" in English.
In this sentence, "marţi" refers to the day of the week (Tuesday) on which the action will take place.
Marţi voi merge la muzeu cu prietenii mei.
On Tuesday, I will go to the museum with my friends.
Here, "marţi" indicates the deadline for the decision, specifying the importance of the given day for taking an action.
Să te hotărăşti până marţi, pentru că vreau să ştiu dacă vii sau nu.
Decide by Tuesday because I want to know if you are coming or not.
In this example, "marţi" is used as a point in the timeline to contextualize the passage of time.