der Dienstag
Tuesday
The second day of the week, which follows Monday and comes before Wednesday.
Ich habe am Dienstag einen wichtigen Termin beim Arzt.
I have an important doctor's appointment on Tuesday.

Tuesday
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Tuesday
The second day of the week, which follows Monday and comes before Wednesday.
Ich habe am Dienstag einen wichtigen Termin beim Arzt.
I have an important doctor's appointment on Tuesday.

To refer to a one-time point in time, you use 'am Dienstag' (on Tuesday). To describe a regular action that takes place every Tuesday, you use the adverb 'dienstags' (on Tuesdays), written in lowercase.
Ich habe am Dienstag einen Zahnarzttermin.
I have a dentist appointment on Tuesday.
'Dienstag' (Tuesday) is often combined with adjectives to specify the time more precisely. Common combinations are 'nächsten Dienstag' (next Tuesday), 'letzten Dienstag' (last Tuesday), and 'jeden Dienstag' (every Tuesday).
Wir treffen uns nächsten Dienstag wieder zur gleichen Zeit.
We'll meet again next Tuesday at the same time.
To indicate a specific time of day, Dienstag can be combined with times of day to form one word. This creates words such as Dienstagmorgen (Tuesday morning), Dienstagnachmittag (Tuesday afternoon), or Dienstagabend (Tuesday evening).
Die Besprechung findet am Dienstagnachmittag statt.
The meeting is taking place on Tuesday afternoon.
Monday
'der Montag' and 'der Dienstag' are both weekdays right at the beginning of the week. They are easy to confuse because they come directly after one another. 'Montag' is the day after Sunday and often the first working day. 'Dienstag' comes after that, so it is between Monday and Wednesday. A practical tip: first comes Monday, then Tuesday.

In der Schule schreiben wir am Dienstag einen Test.
At school, we have a test on Tuesday.
Am Montag beginnt mein neuer Kurs.
My new course starts on Monday.