This is the 59th most frequent German word.
drei
The German word "drei" means "three" in English.
The word 'drei' is used here as a cardinal number denoting the quantity of apples purchased.
Ich habe drei Äpfel gekauft.
I bought three apples.
The word 'drei' appears here in its ordinal form ('dritte') to indicate the sequential order of the weekdays.
Der dritte Tag der Woche ist Dienstag.
The third day of the week is Tuesday.
In this context, 'Drei' refers to the specific number assigned to a particular public transport line.