Uhr or Stunde?

English “hour” hides two German words:

• Uhr = the clock time on the wall: Es ist zwei Uhr. (It is two o’clock.)
• Stunde = a length of 60 minutes: Der Kurs dauert zwei Stunden. (The course lasts two hours.)

Asked Wie lange? (how long?), answer with Stunden. Mixing them up is instant beginner-German — this lesson fixes it.